PHP substr经过一定的char，一个substr + strpos优雅的解决方案？

Question

let's say I want to return all chars after some needle char 'x' from:

$source_str = "Tuex helo babe" .

Normally I would do this:

if( ($x_pos = strpos($source_str, 'x')) !== FALSE )
   $source_str = substr($source_str, $x_pos + 1);

Do you know a better/smarter (more elegant way) to do this?

Without using regexp that would not make it more elegant and probably also slower.

Unfortunately we can not do:

$source_str = substr(source_str, strpos(source_str, 'x') + 1);

Because when 'x' is not found strpos returns FALSE (and not -1 like in JS). FALSE would evaluate to zero, and 1st char would be always cut off.

Thanks,

Answer 1

Your first approach is fine: Check whether x is contained with strpos and if so get anything after it with substr .

But you could also use strstr :

strstr($str, 'x')

But as this returns the substring beginning with x , use substr to get the part after x :

if (($tmp = strstr($str, 'x')) !== false) {
    $str = substr($tmp, 1);
}

But this is far more complicated. So use your strpos approach instead.

Answer 2

Regexes would make it a lot more elegant:

// helo babe
echo preg_replace('~.*?x~', '', $str);

// Tuex helo babe
echo preg_replace('~.*?y~', '', $str);

But you can always try this:

// helo babe
echo str_replace(substr($str, 0, strpos($str, 'x')) . 'x', '', $str);

// Tuex helo babe
echo str_replace(substr($str, 0, strpos($str, 'y')) . 'y', '', $str);

Answer 3

I needed just this, and striving to keep it on one line for fun came up with this:

ltrim(strstr($source_str, $needle = "x") ?: $source_str, $needle);

The ternary operator was adapted in 5.3 to allow this to work.

Since PHP 5.3, it is possible to leave out the middle part of the ternary operator. Expression expr1 ?: expr3 returns expr1 if expr1 evaluates to TRUE, and expr3 otherwise.

NB. ltrim will trim multiple matching characters at the start of the string.

Answer 4

if(strpos($source_str, 'x') !== FALSE )
   $source_str = strstr($source_str, 'x');

Less elegant, but without x in the beginning:

if(strpos($source_str, 'x') !== FALSE )
   $source_str = substr(strstr($source_str, 'x'),1);

Answer 5

在$item的末尾附加一个' - '，因此它总是在' - '之前返回字符串，即使$item不包含' - '，因为strpos默认返回第一次出现 ' - '的位置。

substr($item,0,strpos($item.'-','-'))