How to check string contains alphabetic char or not in Golang

How to check string contains alphabetic char or not in Golang

This tutorial explains how to Check Given string contains Alphabetic Characters or not

Golang String characters Examples

The string is a group of characters enclosed in double quotes. Characters can be any of the following types

  • alphabetic characters: Each character contains a letter from lowercase - a to z and uppercase - A to Z.
  • alphanumeric characters: contain alphabetic and numeric characters.
  • Special characters: a character is like %,# ..etc excluding alphabetic and numeric characters.

In this post, You will learn the following things in GoLang.

  • Find String contains alphabetic
  • Check String contains alphabetic using a regular expression
  • Check String contains alphanumeric and special characters

How to check if a string contains alphabetic characters in Golang?

String characters are iterated using the range loop. During each iteration, Check each character for lowercase and uppercase values and return true for Alphabetic and false for not alphabetic.

Here is a code to check if the string contains an alphabet

package main
import (
    "fmt"
)
// Function to check given string contains alphabet characters
func checkStringAlphabet(str string) bool {
    for _, charVariable: = range str {
        if (charVariable < 'a' || charVariable > 'z') && (charVariable < 'A' || charVariable > 'Z') {
            return false
        }
    }
    return true
}

func main() {
    fmt.Println(checkStringAlphabet("Kiran")) // true
    fmt.Println(checkStringAlphabet("123")) // false

}

Output:

true
false

How to check if a string contains alphabetic characters using Golang Regular Expression?

Regular expressions are supported and available in Golang using the regex standard inbuilt package.

It includes checking regular expressions and pattern matching against a text or a string.

The first regular expression pattern is compiled using the MustCompile function and returns an object. MatchString function is used to check matched strings, and Regular Expression is used as regexp.

MustCompile(\`^\[a-zA-Z\]+$\`)

Following regular expression pattern are used

  • ^- Beginning of a string
  • \[ - Character group starting
  • a-z - lowercase letter
  • A-Z - upper case letter
  • \] - Character group end
  • $- String ending
  • \+ - one or more characters

Here is a Program to check String contains Alphabetic using a regular expression

package main

import (
    "fmt"
    "regexp"
)

var isStringAlphabetic = regexp.MustCompile(`^[a-zA-Z]+$`).MatchString

func main() {
    fmt.Println(isStringAlphabetic("kiran")) // true
    fmt.Println(isStringAlphabetic("a1a")) // false
}

Output:

true
false

How to Check if String contains Alphanumeric characters or special characters in Golang

Regular expression pattern is ^\[a-zA-Z0-9\_\]\*$ .

It returns true for alphabetic, numeric, and underscore characters. return false - for special characters.

Here is a program to check a string for Alphabetic and special characters

package main

import (
    "fmt"
    "regexp"
)

var isStringAlphabetic = regexp.MustCompile(`^[a-zA-Z0-9_]*$`).MatchString

func main() {
    fmt.Println(isStringAlphabetic("cloudhadoop")) // true
    fmt.Println(isStringAlphabetic("abc123")) // true
    fmt.Println(isStringAlphabetic("abc_")) // true
    fmt.Println(isStringAlphabetic("abc|}")) // false
    fmt.Println(isStringAlphabetic("%^&abc")) // false

}

When you compile and execute, the output is

true
true
true
false
false

Conclusion

To summarize, You learned multiple programs to check strings containing Alphabetic, Numeric and Special Characters in the Go language.