Explain in detail the use of for loop, break and continue in go language

Catalog

Basic grammar

A conditional cycle that begins and ends

Conditional loop

Infinite loop

Array loop

Use the counter loop

utilize range loop

Map loop

string The traversal

Break and Continue

Basic grammar

and C The grammatical form of language homology , A cycle from beginning to end ,for init; condition; post { }

Conditional while loop ,for condition { }

Infinite loop ,for { }

A conditional cycle that begins and ends sum := 0for i := 0; i < 10; i++ { sum = sum + i}

Be careful ：i Variables cannot be used after the loop ends

Conditional loop count := 0for count < 10 { fmt.Printf("Current count = %v\n", count) count++} Infinite loop

Because the cycle does not stop , Use here break To break the cycle , It will be introduced in detail later

count := 0 for { fmt.Printf("current count = %v\n", count) count++ if count > 10 { break } } Array loop Use the counter loop

similar C Loops in language , We can traverse the array by combining the counter with the array length , At the same time, it can get the array index , As shown in the following example

package mainimport "fmt"func main() { myarray := []string{"a", "b", "c", "d"} for i := 0; i < len(myarray); i++ { fmt.Printf("Array index is %v, value is %v\n", i, myarray[i]) }} utilize range loop

utilize range It is easier to cycle , also range It can also be used for slice,channel and map In the cycle of

package mainimport "fmt"func main() { myarray := []string{"a", "b", "c", "d"} for index, item := range myarray { fmt.Printf("current index is %v, value is %v\n", index, item) }}Map loop

Introducing Map when , We have tried to use for Cycle pair Map Traversal , Let's consolidate

package mainimport "fmt"func main() { mymap := map[int]string{1 : "a", 2 : "b", 3 : "c"} for key, value := range mymap { fmt.Printf("current key is %v, value is %v\n", key, value) }}

If you just want to get key, You can use , Omit value

for key := range mymap {

Or use _, As mentioned earlier _ Cannot be used for variable , Like a placeholder

for _, value := range mymap {string The traversal

The following example is for string Type traversal , Except for ordinary characters , about Unicode Character segmentation , Characters are usually 8 Bit ,UTF-8 The highest possible character of is 32 Bit

package mainimport "fmt"func main() { mystr := "abc" for pos, char := range mystr { fmt.Printf("character '%c' starts at byte position %d\n", char, pos) } for pos, char := range "Gő!" { fmt.Printf("character '%c' starts at byte position %d\n", char, pos) }}

character 'G' starts at byte position 0
character 'ő' starts at byte position 1
character '!' starts at byte position 3

Break and Continue

Consistent with most languages

Break End the current cycle

Continue Start the next cycle

package mainimport "fmt"func main() { for i := 0; i < 10; i++ { if i == 3 { fmt.Printf("For continue at here: %d\n", i) continue } if i > 5 { fmt.Printf("For break at here: %d\n", i) break } fmt.Printf("Current for count: %d\n", i) } fmt.Println("For loop end here")}

Output results

Current for count: 0
Current for count: 1
Current for count: 2
For continue at here: 3
Current for count: 4
Current for count: 5
For break at here: 6
For loop end here

Not recommended

Go China also supports Lable The way , similar Goto, Generally not used

J: for j := 0; j < 5; j++ { for i := 0; i < 10; i++ { if i > 5 { break J } fmt.Println(i) } }

Here is a detailed explanation of Go In language for loop ,break and continue This is the end of the article on the use of , More about Go Language for break continue Please search the previous articles of software development network or continue to browse the relevant articles below. I hope you will support software development network more in the future ！