正则表达式以匹配字母或数字或空格

Question

can somebody help me with a regular expression whichreturns true only if the string has alphabets or alphabet with spaces.. the string can have numbers or alphabets or alphabets with spaces.

this is what i have tried

/^[ a-zA-Z0-9]+$

Answer 1

You can try the following regular expression:

[\p{Alnum} ]+

Explanation of the regular expression:

NODE             EXPLANATION
---------------  ------------------------------------------
[\p{Alnum} ]+    any character of: letters and digits, ' '
                 (1 or more times (matching the most amount
                 possible))

Additionally, if you plan to use the regular expression very often, it is recommended to use a constant in order to avoid recompile it each time, eg:

private static final Pattern REGEX_PATTERN = 
        Pattern.compile("[\\p{Alnum} ]+");

public static void main(String[] args) {
    String input = ...

    System.out.println(
        REGEX_PATTERN.matcher(input).matches()
    );
}