Golang string processing summary

1. Statistics of string length: len(str)

The len(str) function is used to count the length of strings by bytes. This function is a built-in function and does not need to be imported. It can be used directly. The example is as follows:

//统计字符串的长度,按字节进行统计:
str := "golang你好"//在golang中， 汉字是utf-8字符集，一个汉字3个字节
fmt.Print1n(len(str))//12字节

2. String traversal

(1) Utilization method 1: for-range key value loop

//对字符串进行遍历:
//方式1:利用键值循环: for-range
for i,value := range str {
    fmt.Printf("索引为: %d, 具体的值为: %c \n", i, value)
}

The results are as follows: 

(2) Utilization method 2: r:=[]rune(str)

//方式2:利用r:=[ ]rune(str)
r:=[]rune(str)
fori:=0;i<len(r);i++{
    fmt. Printf("%c \n" ,r[i])
}

The result is as follows:

3. Convert string to integer: Atoi

n, err := strconv.Atoi("66") 

4. Convert integer to string: Itoa          

str = strconv.Itoa(6887)

5. Find whether the substring is in the specified string: Contains

 strings.Contains("javaandgolang", "go")

6. Count how many specified substrings a string has: Count

//统计一个字符串有几个指定的子串:
count := strings.Count("golangandjavaga", ga")
fmt.Println(count)    //2

7. Case-insensitive string comparison: EqualFold

//不区分大小写的字符串比较:
flag := strings.EqualFold("hello","HELLO")
fmt.Println(flag)//true
//区分大小写进行字符串比较:
fmt.Println("hello"=="Hello")//false

8. Return the index value of the first occurrence of the substring in the string. If not, return -1: lndex

//返回子串在字符串第一次出现的索引值，如果没有返回-1 :
fmt.Println(strings.Index("golangandjavaga" ,”ga0"))

9. String replacement: Replace

//strings.Replace("goandjavagogo", "go", "golang", n) 
//n可以指定你希望替换几个，如果n=-1表示全部替换，替换两个n就是2

func main(){
    //字符串的替换:
    str1 := strings.Replace("goandjavagogo","go","golang", -1)
    str2 := strings.Replace("goandjavagogo", "go","golang"，2)
    fmt.Print1n(str1)
    fmt .Print1n(str2)
}

The result is as follows:

10. Split a string into a string array according to a specified character as the split identifier: Split

//按照指定的某个字符，为分割标识，将一个学符串拆分成字符串数组:
arr := strings.Split(" go-python-java", "-")
fmt.Print1n(arr)

11. Convert string letters to uppercase and lowercase

//将字符串的字母进行 大小写的转换:
fmt.Println(strings. ToLower("Go"))
fmt.Println(strings. ToUpper("go"))

12. Remove the spaces on the left and right sides of the string

//将字符串左右两边的空格去掉:
fmt.Println(strings.TrimSpace("  go and java  "))

13. Remove the specified characters on the left and right sides of the string

//将字符串左右两边指定的字符去掉:
fmt.Println(strings.Trim("~golang~","~"))

14. Remove the specified characters on the left side of the string

strings.TrimLeft("~golang~", "~")

15. Remove the specified characters on the right side of the string

strings.TrimRight("~golang~", "~")

16. Determine whether a string begins with the specified string

strings.HasPrefix("http://java.sun.com/jsp/jstl/fmt", "http")

17. Determine whether the string ends with the specified string

strings.HasSuffix("demo.png", ".png")