Ответы и вопросы по оценке навыков LinkedIn – Go (Язык программирования)

Идти is a popular programming language that offers many benefits for developers, например, параллелизм, простота, и производительность. If you want to learn Идти or improve your skills, you might be interested in taking the Оценка навыков LinkedIn за Идти. This is a test that measures your proficiency in Идти and gives you a badge to showcase your achievement on your profile. тем не мение, passing the test is not easy, and you might need some help to prepare for it.

That’s why I have compiled a list of Ответы и вопросы по оценке навыков в LinkedIn за Идти that you can use to study and practice. В этом сообщении в блоге, I will share with you these questions and answers, along with some explanations and tips. By reading this post, you will gain valuable insights into the topics and concepts that are covered in the Оценка навыков LinkedIn за Идти, and you will be able to ace the test with confidence.

Q1. What do you need for two functions to be the same type?

They should share the same signatures, including parameter types and return types.
They should share the same parameter types but can return different types.
All functions should be the same type.
The functions should not be a first class type.

User defined function types in Go (Golang)

2 квартал. What does the `len()` function return if passed a UTF-8 encoded string?

the number of characters
the number of bytes
It does not accept string types.
the number of code points

Length of string in Go (Golang).

3 квартал. Который не a valid loop construct in Go?

      do { ... } while i < 5

      for _,c := range "hello" { ... }

      for i := 1; i < 5; i++ { ... }

      for i < 5 { ... }

Каждый слой и все они выровнены одновременно: Go has only for-петли

4 квартал. How will you add the number 3 to the right side?

values := []int{1, 1, 2}

      values.append(3)

      values.insert(3, 3)

      append(values, 3)

      values = append(values, 3)

Каждый слой и все они выровнены одновременно: slices in GO are immutable, so calling append does not modify the slice

Q5. What is the value of `Read`?

const (
  Write = iota
  Read
  Execute
)

0
1
2
a random value

IOTA in Go (Golang)

Q6. Which is the только valid import statement in Go?

      import "github/gin-gonic/gin"

      import "https://github.com/gin-gonic/gin"

      import "../template"

      import "github.com/gin-gonic/gin"

Import in GoLang

Q7. What would happen if you attempted to compile and run this Go program?

package main
var GlobalFlag string
func main() {
  print("["+GlobalFlag+"]")
}

It would not compile because GlobalFlag was never initialized.
It would compile and print [].
It would compile and print nothing because "[" +nil+"]" это также nil.
It would compile but then panic because GlobalFlag was never initialized.

переменные in Go have initial values. For string type, it’s an empty string.
Go Playground

Q8. From where is the variable `myVar` accessible if it is declared outside of any functions in a file in package `myPackage` located inside module `myModule`?

It can be accessed anywhere inside myPackage, not the rest of myModule.
It can be accessed by any application that imports myModule.
It can be accessed from anywhere in myModule.
It can be accessed by other packages in myModule as long as they import myPackage

Каждый слой и все они выровнены одновременно: to make the variable available outside of myPackage change the name to MyVar. See also an example of Exported names in the Tour of Go.

Q9. How do you tell `go test` to print out the tests it is running?

go test
go test -x
go test --verbose
go test -v

test package

Q10. This code printed `{0, 0}`. How can you fix it?

type Point struct {
  x int
  y int
}

func main() {
  data := []byte(`{"x":1, "y": 2}`)
  var p Point
  if err := json.Unmarshal(data, &p); err != nil {
    fmt.Println("error: ", err)
  } else {
    fmt.Println(p)
  }
}

использование json.Decoder
Pass a pointer to data
Делать X а также Y exported (uppercase)
Use field tags

Вам нужно будет достичь как минимум. What does a `sync.Mutex` block while it is locked?

all goroutines
any other call to lock that Mutex
any reads or writes of the variable it is locking
any writes to the variable it is locking

Mutex in GoLang, sync.Mutex locks so only one goroutine at a time can access the locked variable.
sync.Mutex

Q12. What is an idiomatic way to pause execution of the current scope until an arbitrary number of goroutines have returned?

Pass an int а также Mutex to each and count when they return.
Loop over a select заявление.
Sleep for a safe amount of time.
sync.WaitGroup

Каждый слой и все они выровнены одновременно: this is exactly what sync.WaitGroup is designed for – Use sync.WaitGroup in Golang

Q13. What is a side effect of using `time.After` в `select` заявление?

It blocks the other channels.
It is meant to be used in select statements without side effects.
It blocks the select statement until the time has passed.
The goroutine does not end until the time passes.

Заметка: it doesn’t block select and does not block other channels.

Q14. What is the select statement used for?

executing a function concurrently
executing a different case based on the type of a variable
executing a different case based on the value of a variable
executing a different case based on which channel returns first

Select statement in GoLang

Q15. According to the Go documentation standard, how should you document this function?

func Add(a, b int) {
        return a + b
}

// Calculate a + b
// - a: int
// - b: int
// - returns: int
func Add(a, b int) {
        return a + b
}

// Does a + b
func Add(a, b int) {
        return a + b
}

// Add returns the sum of a and b
func Add(a, b int) {
        return a + b
}

// returns the sum of a and b
func Add(a, b int) {
        return a + b
}

Каждый слой и все они выровнены одновременно: documentation block should start with a function name

Comments in Go

Q16. What restriction is there on the type of `var` to compile this `i := myVal.(int)?`

myVal must be an integer type, такие как int, int64, int32, так далее.
myVal must be able to be asserted as an int.
myVal must be an interface.
myVal must be a numeric type, такие как float64 или же int64.

Каждый слой и все они выровнены одновременно: This kind of type casting (с помощью .(type)) is used on interfaces only.

Q17. What is a channel?

a global variable
a medium for sending values between goroutines
a dynamic array of values
a lightweight thread for concurrent programming

Channels

Q18. How can you make a file build only on Windows?

Check runtime.GOOS.
Add a // +build windows comment anywhere in the file.
Add a _ prefix to the file name.
Add a // +build windows comment at the top of the file.

//go:build windows “Go versions 1.16 and earlier used a different syntax for build constraints, с “// +строить” prefix. The gofmt command will add an equivalent //go:build constraint when encountering the older syntax.”

Q19. What is the correct way to pass this as a body of an HTTP POST request?

data := "A group of Owls is called a parliament"

  resp, err := http.Post("https://httpbin.org/post", "text/plain", []byte(data))

      resp, err := http.Post("https://httpbin.org/post", "text/plain", data)

      resp, err := http.Post("https://httpbin.org/post", "text/plain", strings.NewReader(data))

      resp, err := http.Post("https://httpbin.org/post", "text/plain", &data)

Q20. What should the idiomatic name be for an interface with a single method and the signature `Save() error`?

Saveable
SaveInterface
ISave
Saver

Effective Go, Interface names

Q21. А `switch` заявление _ its own lexical block. каждый `case` заявление _ an additional lexical block

does not create; creates
does not create; does not create
creates; creates
creates; does not create

Go Language Core technology (Volume one) 1.5-объем

Relevant excerpt from the article:

The second if statement is nested inside the first, so a variable declared in the first if statement is visible to the second if statement. There are similar rules in switch: Each case has its own lexical block in addition to the conditional lexical block.

Q22. What is the default case sensitivity of the JSON `Unmarshal` функция?

The default behavior is case insensitive, but it can be overridden.
Fields are matched case sensitive.
Fields are matched case insensitive.
The default behavior is case sensitive, but it can be overridden.

encoding/json#Unmarshal

Relevant excerpt from the article:

To unmarshal JSON into a struct, Unmarshal matches incoming object keys to the keys used by Marshal (either the struct field name or its tag), preferring an exact match but also accepting a case-insensitive match. По умолчанию, object keys which don’t have a corresponding struct field are ignored (see Decoder.DisallowUnknownFields for an alternative).

Q23. В чем разница между `time` package’s `Time.Sub()` а также `Time.Add()` методы?

Time.Add() is for performing addition while Time.Sub() is for nesting timestamps.
Time.Add() always returns a later time while time.Sub always returns an earlier time.
They are opposites. Time.Add(Икс) is the equivalent of Time.Sub(-Икс).
Time.Add() accepts a Duration parameter and returns a Time while Time.Sub() accepts a Time parameter and returns a Duration.

Q24. What is the risk of using multiple field tags in a single struct?

Every field must have all tags to compile.
It tightly couples different layers of your application.
Any tags after the first are ignored.
Missing tags panic at runtime.

Q25. Where is the built-in recover method useful?

in the main function
immediately after a line that might panic
inside a deferred function
at the beginning of a function that might panic

Example of Recover Function in Go (Golang)

Relevant excerpt from the article:

Recover is useful only when called inside deferred functions. Executing a call to recover inside a deferred function stops the panicking sequence by restoring normal execution and retrieves the error message passed to the panic function call. If recover is called outside the deferred function, it will not stop a panicking sequence.

Q26. Which choice does не send output to standard error?

println(message)
log.New(os.Stderr, "", 0).Println(message)
fmt.Errorf("%s\n", message)
fmt.Fprintln(os.Stderr, message)

func println: writes the result to standard error.
func New: func New(out io.Writer, prefix string, flag int) *Logger; the out variable sets the destination to which log data will be written.
func Errorf: Errorf formats according to a format specifier and returns the string as a value.
func Fprintln: func Fprintln(w io.Writer, a …любой) (n int, err error); Fprintln formats using the default formats for its operands and writes to w.

Q27. How can you tell Go to import a package from a different location?

Use a proxy.
Change the import path.
Use a replace directive in go.mod.
Use a replace directory.

Call your code from another module: глава 5., go mod edit -replace example.com/greetings=../greetings.
go.mod replace directive

Q28. If your current working directory is the top level of your project, which command will run all its test packages?

go test all
go run --all
go test .
go test ./...

Relevant excerpt from the article:

Relative patterns are also allowed, как “go test ./…” to test all subdirectories.

Q29. Which encodings can you put in a string?

любой, it accepts arbitary bytes
any Unicode format
UTF-8 or ASCII
UTF-8,

Strings, байты, runes and characters in Go

Relevant excerpt from the article:

Короче, Go source code is UTF-8, so the source code for the string literal is UTF-8 text.

Example of encoding in Go (Golang)

Relevant excerpt from the article:

Package encoding defines an interface for character encodings, such as Shift JIS and Windows 1252, that can convert to and from UTF-8.

Q30. How is the behavior of `t.Fatal` different inside a `t.Run`?

There is no difference.
t.Fatal does not crash the test harness, preserving output messages.
t.Fatal stops execution of the subtest and continues with other test cases.
t.Fatal stops all tests and contains extra information about the failed subtest.

Ссылка:
testing package in Go, the relevant excerpt from the article:

Fatal is equivalent to Log followed by FailNow. Log formats its arguments using default formatting, analogous to Println, and records the text in the error log. FailNow marks the function as having failed and stops its execution by calling runtime.Goexit (which then runs all deferred calls in the current goroutine). Execution will continue at the next test or benchmark. FailNow must be called from the goroutine running the test or benchmark function, not from other goroutines created during the test. Звонок FailNow does not stop those other goroutines. Run бежит f as a subtest of t called name. It runs f in a separate goroutine and blocks until f returns or calls t.Parallel to become a parallel test. Run reports whether f succeeded (or at least did not fail before calling t.Parallel). Run may be called simultaneously from multiple goroutines, but all such calls must return before the outer test function for t returns.

Q31. What does `log.Fatal` делать?

It raises a panic.
It prints the log and then raises a panic.
It prints the log and then safely exits the program.
It exits the program.

Example of func Fatal in Go (Golang)

Relevant excerpt from the article:

Fatal is equivalent to Print() followed by a call to os.Exit(1).

Q32. Which is a valid Go time format literal?

“2006-01-02”
“YYYY-mm-dd”
“y-mo-d”
“year-month-day”

func Time in Go

Relevant excerpt from the article:

Year: "2006" "06"
Month: "Jan" "January" "01" "1"
Day of the week: "Mon" "Monday"
Day of the month: "2" "_2" "02"
Day of the year: "__2" "002"
Hour: "15" "3" "03" (PM or AM)
Minute: "4" "04"
Second: "5" "05"
AM/PM mark: "PM"

довольно часто____. How should you log an error (err)

log.Error(err)
log.Printf("error: %v", err)
log.Printf(log.ERROR, err)
log.Print("error: %v", err)

Каждый слой и все они выровнены одновременно: There is defined neither log.ERROR, nor log.Error() в log package in Go; log.Print() arguments are handled in the manner of fmt.Print(); log.Printf() arguments are handled in the manner of fmt.Printf().

Q34. Which file names will the `go test` command recognize as test files?

any that starts with test
any files that include the word test
only files in the root directory that end in _test.go
any that ends in _test.go

Test packages in go command in Go: ‘Go test’ recompiles each package along with any files with names matching the file pattern “*_test.go”.
Add a test in Go

Каждый слой и все они выровнены одновременно. What will be the output of this code?

ch := make(chan int)
ch <- 7
val := <-ch
fmt.Println(val)

0
It will deadlock
It will not compile
2.718

Go Playground share, output:

fatal error: all goroutines are asleep - deadlock!

goroutine 1 [chan send]:
main.main()
 /tmp/sandbox2282523250/prog.go:7 +0x37

Program exited.

Q36. What will be the output of this program?

ch := make(chan int)
close(ch)
val := <-ch
fmt.Println(val)

It will deadlock
It will panic
0
NaN

The Go Programming Language Specification “Receive operator”, Relevant excerpt from the article:

A receive operation on a closed channel can always proceed immediately, yielding the element type’s zero value after any previously sent values have been received.
Go Playground share, output:

0

Program exited.

Q37. What will be printed in this code?

var stocks map[string]float64 // stock -> price
price := stocks["MSFT"]
fmt.Printf("%f\n", price)

0
0.000000
The code will panic
NaN

Go Playground share, output:

0.000000

Program exited.

Q38. What is the common way to have several executables in your project?

Have a cmd directory and a directory per executable inside it.
Comment out main.
Use build tags.
Have a pkg directory and a directory per executable inside it.

Q39. How can you compile main.go to an executable that will run on OSX arm64 ?

Set GOOS to arm64 and GOARCH to darwin.
Set GOOS to osx and GOARCH to arm64.
Set GOOS to arm64 and GOARCH to osx.
Set GOOS to darwin and GOARCH to arm64.

документация

Q40. What is the correct syntax to start a goroutine that will `print Hello Gopher!`?

go(fmt.Println("Hello Gopher!"))
go func() { fmt.Println("Hello Gopher!") }
go fmt.Println("Hello Gopher!")
Go fmt.Println("Hello Gopher!")

Example of start a goroutine

Q41. If you iterate over a map in a for range loop, in which order will the key:value pairs be accessed?

in pseudo-random order that cannot be predicted
in reverse order of how they were added, last in first out
sorted by key in ascending order
in the order they were added, first in first out

Ссылка

Q42. What is an idiomatic way to customize the representation of a custom struct in a formatted string?

There is no customizing the string representation of a type.
Build it in pieces each time by calling individual fields.
Implement a method String() string
Create a wrapper function that accepts your type and outputs a string.

Ссылка

Q43. How can you avoid a goroutine leak in this code?

func findUser(ctx context.Context, login string) (*User, error) {
    ch := make(chan *User)
    go func() {
            ch <- findUserInDB(login)
    }()

    select {
    case user := <-ch:
            return user, nil
    case <-ctx.Done():
            return nil, fmt.Errorf("timeout")
    }
}

Use a sync.WaitGroup.
Make ch a buffered channel.
Add a default case to the select.
Use runtime.SetFinalizer.

Ссылка

Relevant excerpt from the article:

The simplest way to resolve this leak is to change the channel from an unbuffered channel to a buffered channel with a capacity of 1. Now in the timeout case, after the receiver has moved on, the Goroutine will complete its send by placing the *User value in the channel then it will return.

44. What will this code print?

var i int8 = 120
i += 10
fmt.Println(i)

-126
0
NaN
130

Go Playground example, output:

-126

Program exited.

45. Given the definition of worker below, what is the right syntax to start a goroutine that will call worker and send the result to a channel named ch?

func worker(m Message) Result

go func() {
    r := worker(m)
    ch <- r
}

go func() {
    r := worker(m)
    r -> ch
} ()

go func() {
    r := worker(m)
    ch <- r
} ()

go ch <- worker(m)

Go Playground example

Q46. In this code, which names are exported?

package os

type FilePermission int
type userID int

FilePermission
none of these answers
FilePermission and userID
userID

Ссылка 1 Ссылка 2

Q47. Which of the following is correct about structures in Go?

Structure is another user defined data type available in Go programming, which allows you to combine data items of different kinds.
Structures are used to represent a record
To define a structure, you must use type and struct statements.
Все вышеперечисленное

Q48. What does the built-in `generate` command of the Go compiler do?

It provides subcommands sql, json, yaml, and switches --schema а также --objects to generate relevant code.
It looks for files with names that end with _generate.go, and then compiles and runs each of these files individually.
It scans the projects source code looking for //go:generate Комментарии, and for each such comment runs the terminal command it specifies.
It has subcommands mocks а также tests to generate relevant .go source files.

Generate Go files by processing source

Q49. Using the time package, how can you get the time 90 minutes from now?

time.Now().Add(90)
time.Now() + (90 * time.Minute)
time.Now() + 90
time.Now().Add(90 * time.Minute)

func (Время) Add example

Q50. A program uses a channel to print five integers inside a goroutine while feeding the channel with integers from the main routine, but it doesn’t work as is. What do you need to change to make it work?

Add a close(ch) незамедлительно после wg.Wait().
Add a second parameter to make(chan, int), например. make(chan int, 5).
Remove the use of unnecessary WaitGroup звонки, например. all lines that start with wg.
Move the 7-line goroutine immediately after wg.Add(1) to a line immediately before wg.Wait().

Ссылка

Relevant excerpt from the article:

The simplest way to resolve this leak is to change the channel from an unbuffered channel to a buffered channel with a capacity of 1. Now in the timeout case, after the receiver has moved on, the Goroutine will complete its send by placing the *User value in the channel then it will return.

Q51. After importing `encoding/json`, how will you access the `Marshal` функция?

encoding.json.Marshal
encoding/json.Marshal
Marshal
json.Marshal

encoding/json#Marshal example

Q52. What are the two missing segments of code that would complete the use of `context.Context` to implement a three-second timeout for this HTTP client making a GET request?

package main

import (
        "context"
        "fmt"
        "net/http"
)

func main() {
        var cancel context.CancelFunc
        ctx := context.Background()

        // #1: <=== What should go here?

        req, _ := http.NewRequest(http.MethodGet,
                "https://linkedin.com",
                nil)

        // #2: <=== What should go here?

        client := &http.Client{}
        res, err := client.Do(req)
        if err != nil {
                fmt.Println("Request failed:", err)
                return
        }
        fmt.Println("Response received, status code:",
                res.StatusCode)
}

      ctx.SetTimeout(3*time.Second)
      req.AttachContext(ctx)

      ctx, cancel = context.WithTimeout(ctx, 3*time.Second); defer cancel()
      req = req.WithContext(ctx)

      ctx, cancel = context.WithTimeout(ctx, 3*time.Second); defer cancel() #2: req.AttachContext(ctx)

      ctx.SetTimeout(3*time.Second)
      req = req.WithContext(ctx)

Q53. If you have a struct named Client defined in the same .go file as the statement, how do you export a variable with a default value so the variable is accessible by other packages?

```
let Default := new Client()
```
```
public default = &Client()
```
```
var Default = &Client{}
```
```
export default := new Client{}
```

Q54. This program outputs `{Master Chief Spartan Protagonist Halo}`. How would you get it to output `Master Chief - a Spartan - is the Protagonist of Halo` вместо?

package main

import "fmt"

type Character struct{
        Name  string
        Class string
        Role  string
        Game  string
}

func main() {
        mc := Character{
                Name: "Master Chief",
                Class: "Spartan",
                Role: "Protagonist",
                Game: "Halo",
        }
        fmt.Println(mc)
}

// Replace
// fmt.Println(mc)
// with this:

fmt.Printf("(?P<Name>) - a (?P<Class>) - is the (?P<Role>) of (?P<Game>)", mc)

// Replace
// fmt.Println(mc)
// with this:
fmt.Println(mc, func(c Character) string {
      return c. Name + " - a " + c.Class + " - is the " + c.Role + " of " + c.Game
})

// add this to the package `main`

func (c Character) String() string {
      return fmt.Sprintf("%s - a %s - is the %s of %s", c.Name, c.Class, c.Role,c.Game)
}

 // add this to the package `main`

func (c Character) OnPrint() {
      fmt.Println("{{c.Name}} - a {{c.Class}} - is the {{c.Role}} of {{c.Game}}")
}

fmt#Stringer

Q55. How would you implement a working `Append()` method for `Clients`?

package main

type Client struct {
  Name string
}
type Clients struct {
  clients []*Client
}
func main() {
  c:= &Clients{clients.make([]*Client,0)}
  c.Append(&Client{Name: "LinkedIn API})
}

func (cc *Clients) Append(c *Client) {
  cc.clients = append(cc.clients, c)
}

func (cc *Clients) Append(c *Client) {
  cc.append(c)
}

func (cc Clients) Append(c Client) {
  cc.clients = append(cc.clients, c)
}

func (cc *Clients) Append(c Client) {
  cc.clients.append(c)
}

Q56. How would you recover from a `panic()` thrown by a called function without allowing your program to fail assuming your answer will run in the same scope where your function call will experience the panic?

Wrap the function call in an anonymous function with a return type of panic, remembering to invoke the anonymous function by suffixing it with () then introspecting the returned panic instance to handle the error.
использование try{ ... } to wrap the code calling the function and then handle the error within the catch{ ... }.
использование defer func { ... }() before the function call with the error and then handle the panic inside the anonymous function.
Prefix the function call with @ to force return the panic as an error value and then handle the error just as you would an error returned by any function.

Q57. What will this code print?

var n int
fmt.Println (n)

0
nil
a random value
1

This is because in Go, when a variable is declared but not explicitly initialized, it is assigned a default zero value based on its type. For integers like n, the zero value is 0.

Q58. When creating a formatted string, which verb should you use to call the String () string method of a custom type?

%s
%б
%v
%string

In Go, the %s verb is used to format a string. When used with a custom type that has a String() method defined, the String() method will be automatically called and its return value will be used in the formatted string.

Q59. Which is not a valid value for layout when calling time. Сейчас ( ) . Формат ( макет)?

time.REC3339
“1970-01-01”
“Jan 2nd 2006”
time.Kitchen

time#Time.Format

According to the documentation, the value 1 а также 01 will represent the current month.

each layout string is a representation of the time stamp,
	Jan 2 15:04:05 2006 MST
An easy way to remember this value is that it holds, when presented in this order, the values (lined up with the elements above):
	  1 2  3  4  5    6  -7

Q60. How would you signal to the Go compiler that the Namespace struct must implement the JSONConverter interface? This question assumes the answer would be included in the same package where Namespace is declared.

var_JSONConverter = nil. (*Пространство имен)
var_JSONConverter = (*Пространство имен) (nil)
type Namespace struct { implements JSONConverter // The rest of the struct declaration goes here }
type Namespace struct { JSONConverter // The rest of the struct declaration goes here }

This syntax creates a variable _ with the type of JSONConverter and assigns to it a value of (*Пространство имен)(nil). This essentially checks that the Namespace struct satisfies the JSONConverter interface by ensuring that it can be assigned to a variable of type JSONConverter.

Q61. Which statement about typing and interfaces is false?

A method signature is the combination of a method name and the type(s) of its declared parameter(s) and return value(s).
A struct must explicitly declare using the implements keyword that its instances can be used wherever a variable, parameter, and/or return value is typed for the declared interface.
An interface declares a list of methods and their signatures that a type must implement to be compatible with values typed for that interface.
Variable, parameters, and return values must be “typed” в качестве одного из 1) a built-in type, 2) a type alias, 3) a derived type, 4) a composite type, или же

an interface.

In Go, a type automatically satisfies an interface if it implements all the methods of that interface. There is no need to explicitly declare that a struct implements an interface using a specific keyword.

Q62. How would you complete this program to generate the specified output, assuming the SQL table

===[Output]================
1: &{GameId:1 Title:Wolfenstein YearReleased:1992}
2: &{GameId:2 Title:Doom YearReleased:1993}
3: &{GameId:3 Title:Quake YearReleased:1996}

===[main.go]================
package main

import (
        "database/sql"
        "fmt"
        _ "github.com/go-sql-driver/mysql"
        "log"
)

type Game struct {
        GameId       int
        Title        string
        YearReleased int
}

func main() {

        conn, err := sql.Open("mysql",
                "john_carmack:agiftw!@tcp(localhost:3306)/idsoftware")

        if err != nil {
                panic(err)
        }
        defer func() { _ = conn.Close() }()

        results, err := conn.Query("SELECT game_id,title,year_released FROM games;")
        if err != nil {
                panic(err)
        }
        defer func() { _ = results.Close() }()

        // #1 <=== What goes here?

        for results.Next() {
                var g Game

                // #2 <=== What goes here?

                if err != nil {
                        panic(err)
                }

                // #3 <=== What goes here?

        }

        for i, g := range games {
                fmt.Printf("%d: %+v\n", i, g)
        }

}

#1: games := make([]*Game, results.RowsAffected())
#2: g, err = results.Fetch()
#3: games[results.Index()] = &g

#1: games := []Game{}
#2: g, err = results.Fetch()
#3: games = append(games,g)

#1: games := map[int]Game{}
#2: err = results.Scan(&g)
#3: games[g.GameId] = g

#1: games := make(map[int]*Game, 0)
#2: err = results.Scan(&g.GameId, &g.Title, &g.YearReleased)
#3: games[g.GameId] = &g

Q63. Fill in the blanks

Test files in Go must _.
Individual tests are identified by _.
You can run subtests by __.
You log the error and mark the test failed by _.

be stored in a /test/subdirectory of that package
functions accepting a testing.Tester parameter
writing functions with names matching ^Subtest
вызов testing.AssertionFailed
end in _test.go
function names matching ^Test[A-Z]
вызов t.Run()
вызов t.Errorf()
begin with test_
functions matching [a-z]Test$
вызов testing.Subtest()
allowing testing.Assert() to fail its assertion
be stored in /test/ root subdirectory for the project
functions accepting a testing.Test parameter
passing closures to testing.AddSubtest()
returning an error from the function

Q64. Which type is a rune an alias for?

char
byte
int32
string

Strings, байты, runes and characters in Go

Relevant excerpt from the article:

The Go language defines the word rune as an alias for the type int32, so programs can be clear when an integer value represents a code point.

Q65. When can you use the := syntax to assign to multiple variables? Например:

x, err := myFunc()

if it at least has not been declared in that lexical block
at all times, as it will overwrite existing variables
if no variables of those names is accessible
if none of the variables exist in that lexical block

Short variable declarations

Q66. How can You view the profiler output in cpu.pprof in the browser?

go pprof -to SVG cpu.prof
go tool pprof -http=:8080 cpu.pprof (истинный)
go tool pprof cpu.pprof
go tool trace cpu.pprof

Q67. When does a variable of type interface{} evaluate to nil?

It has been assingned a dynamic type whose value is nil. (истинный)
It has been explicitly set to nil.
It has not been assigned a dynamic type.
It can not evaluate to nil.

Q68. What value does a string variable hold if it has been allocated but not assigned?

nil
undefined
null
“”

If a string variable has been allocated but not assigned a value, its default value is an empty string “”. In Go, uninitialized string variables are automatically assigned the zero value for their respective type, which for strings is an empty string.

Q69. Which built-in function is used to stop a program from continuing?

panic
There is no such function.
raiseException
exit

The built-in function used to stop a program from continuing is panic(). Когда panic() называется, it triggers a panic, which stops the normal execution flow of the program and begins panicking. If the panic is not recovered, the program terminates.

Q70. What will the output be?

a,b := 1, 2
b,c:= 3, 4
fmt.Println(a, b, c)

1 3 4
1 2 3
1 2 4
It will not compile.

Go Playground Example

Q71. What is the operator for a logical AND condition?

+
а также
&&
||

Контроль опасностей технологической безопасности. What is an anonymous function in Go?

A function with no return type.
A function with no parameters.
A function without a name.
A function declared inside another function.

Q73.Which keyword is used to declare an anonymous function in Go?

func
lambda
func()
anonymous

Контроль опасностей технологической безопасности. What is the main advantage of using anonymous functions in Go?

They always have better performance than named functions.
They can have multiple return values.
They can be defined inline where they are used.
They have a shorter syntax than named functions.

Каждый слой и все они выровнены одновременно: they can be defined inline where they are used, offering more flexibility in code organization.

Q75. What is the syntax for calling an anonymous function immediately after its declaration in Go?

functionName(){}
call functionName(){}
func(){}()
execute func(){}

ссылка

Q76. Which types can Go developers define methods for?

all named types not built-in to Go, such as type Example int but not int, type Example struct{...} but not struct, etc.
only types named struct, map, and slice, such as type Example struct{…}
only types named struct, such as type Example struct{...}
all types

Methods can be defined for any named type that is not a built-in type. When you create a new type using a type declaration, it becomes a named type, and you can define methods specific to that type. тем не мение, methods cannot be directly attached to built-in types like int, string, так далее. ссылка

Автор

Хелен Бэсси

Привет, I'm Helena, автор блога, который любит публиковать познавательный контент в нише образования. Я считаю, что образование является ключом к личному и социальному развитию., и я хочу поделиться своими знаниями и опытом с учащимися всех возрастов и слоев общества.. В моем блоге, вы найдете статьи на такие темы, как стратегии обучения, онлайн-образование, Профориентация, и более. Я также приветствую отзывы и предложения от моих читателей., так что не стесняйтесь оставлять комментарии или обращаться ко мне в любое время. Надеюсь, вам понравится читать мой блог и вы найдете его полезным и вдохновляющим..
Просмотреть все сообщения

Зарегистрироваться

Авторизоваться

забытый пароль

Добавить запись

Добавить вопрос

Авторизоваться

Зарегистрироваться