Does go language have while?

There is no while keyword in the Go language, and the while and do-while loop structures are not supported. Functionally speaking, anything that the while statement can do, the for statement can also achieve, so the Go language unifies the for statement and the while statement. Moreover, the Go development team has serious mysophobia. While is not a necessary option. It provides multiple ways for developers to choose, which can easily make developers get lost and make it difficult to choose. Therefore, they simply do not give the opportunity to choose and force everyone to unify the style. .

The operating environment of this tutorial: Windows 7 system, GO version 1.18, Dell G3 computer.

There is no while keyword in the go language, , and the while and do-while loop structures are not supported.

Loop statements are used to repeatedly execute statements in certain programs.

Common loop statements in programming languages ​​include while statements, do-while statements and for statements. But there is only for language in Go language, and there is no while statement. Functionally speaking, anything that the while statement can do, the for statement can also do. Therefore, the Go language unifies the for statement and while statement.

And the Go development team has serious mysophobia. While is not a necessary option. It provides multiple ways for developers to choose. It is easy for developers to get lost and make the choice difficult; so simply not give them a chance to choose. , forcing everyone to have a unified style.

for statement

There are three kinds of for statements in Go language:

The first one:

for init; condition; post {
	...	
}

• init It is generally an assignment expression and is used to initialize loop control variables and other variables.
• condition Relational expressions and logical expressions used to indicate loop control conditions.
• post It is generally an assignment expression, used to increase or decrease loop control variables

The above three points are equivalent to the for statement in other programming languages, so the first way of writing is equivalent to for in other languages statement.

The second way:

for condition {
	...
}

The second way of writing is equivalent to the while statement in other languages. Because Go's for statement does not include parentheses, deleting init and post is completely equivalent to the while statement. Therefore, Go does not introduce the while keyword and directly uses the for statement to implement the while statement.

The third way:

for {
	...
}

The third way of writing is equivalent to for( in other languages ;;), also equivalent to while(true).

Example:

package main

import "fmt"

func main() {
	res := 1
	n := 10

	for i:=1; i<=n; i++ {
		res *= i
	}
	fmt.Println(n,"的阶乘是",res)
}

// 10 的阶乘是 3628800

for-each range

Range of for loop in Go language The format can iterate slice, map, array, string and other types. The format is as follows:

for k, v := range oldMap {
	newMap[k] = v
}

Example:

package main

import "fmt"

func main() {
	nums := [5]int{1, 2, 3, 4, 5}
	for i,e := range nums {
		fmt.Println("索引", i, "位置上的数值为", e)
	}
}

// 索引 0 位置上的数值为 1
// 索引 1 位置上的数值为 2
// 索引 2 位置上的数值为 3
// 索引 3 位置上的数值为 4
// 索引 4 位置上的数值为 5

Same as Python and Go language Also use underscores _ to catch unwanted return values.

for _,e := range nums {
	...
}

【Related recommendations: Go video tutorial, Programming teaching】

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