PHP - detect whitespace between strings

问题:

How would I go about detecting whitespace within a string? For example, I have a name string like:

"Jane Doe"

Keep in mind that I don't want to trim or replace it, just detect if whitespace exists between the first and second string.

回答1:

Use preg_match as suggested by Josh:

<?php

$foo = "Dave Smith";
$bar = "SamSpade";
$baz = "Dave\t\t\tSmith";

var_dump(preg_match('/\s/',$foo));
var_dump(preg_match('/\s/',$bar));
var_dump(preg_match('/\s/',$baz));

Ouputs:

int(1)
int(0)
int(1)

回答2:

Wouldn't preg_match("/\s/",$string) work? The advantage to this over strpos is that it will detect any whitespace, not just spaces.

回答3:

You could check for only alphanumerical characters, which whitespace is not. You could also do a strpos for a space.

if(strpos($string, " ") !== false)
{
   // error
}

回答4:

You may use something like this:

if (strpos($r, ' ') > 0) {
    echo 'A white space exists between the string';
}
else
{
    echo 'There is no white space in the string';
}

This will detect a space, but not any other kind of whitespace.

回答5:

http://no.php.net/strpos

<?php
if(strpos('Jane Doe', ' ') > 0)
    echo 'Including space';
else
    echo 'Without space';
?>

回答6:

// returns no. of matches if $str has nothing but alphabets,digits and spaces.
function is_alnumspace($str){
  return preg_match('/^[a-z0-9 ]+$/i',$str);
}

回答7:

// returns no. of matches if $str has nothing but alphabets,digits and spaces. function 

    is_alnumspace($str) {
          return preg_match('/^[A-Za-z0-9 ]+$/i',$str);
    }

// This variation allows uppercase and lowercase letters.