检查字符串是否为int golang

How can I check if a string value is an integer or not in Golang?

Something like

v := "4"
if isInt(v) {
  fmt.Println("We have an int, we can safely cast this with strconv")
}

Note: I know that strconv.Atoi returns an error, but is there any other function to do this?

The problem with strconv.Atoi is that it will return 7 for "a7"

As you said, you can use strconv.Atoi for this.

if _, err := strconv.Atoi(v); err == nil {
    fmt.Printf("%q looks like a number.
", v)
}

You could use scanner.Scanner (from text/scanner) in mode ScanInts, or use a regexp to validate the string, but Atoi is the right tool for the job.

import "fmt"
import "regexp"

func main() {
    youString :="a12345"
    match, _ := regexp.MatchString("([a-z]+)", youString)
    if  !match{
     fmt.Println("Is Number")
    } else{
     fmt.Println("Not Is Number")
    }   


    }

this is better, you can check for ints upto 64 ( or less ) bits

strconv.Atoi only supports 32 bits

if _, err := strconv.ParseInt(v,10,64); err == nil {
    fmt.Printf("%q looks like a number.
", v)
}

try it out with v := "12345678900123456789"

You can use unicode.IsDigit():

import "unicode"

func isInt(s string) bool {
    for _, c := range s {
        if !unicode.IsDigit(c) {
            return false
        }
    }
    return true
}

You can use govalidator.

Code

govalidator.IsInt("123")  // true

Full Example

package main

import (
    "fmt"
    valid "github.com/asaskevich/govalidator"
)

func main() {
    fmt.Println("Is it a Integer? ", valid.IsInt("978"))
}

Output:

$ go run intcheck.go
Is it a Integer?  true

this might help

func IsInt(s string) bool {
    l := len(s)
    if strings.HasPrefix(s, "-") {
        l = l - 1
        s = s[1:]
    }

    reg := fmt.Sprintf("\\d{%d}", l)

    rs, err := regexp.MatchString(reg, s)

    if err != nil {
        return false
    }

    return rs
}