一个Liner将字符串前置或附加到另一个字符串

Not a vital question, just wondering if there is any onliner to do this.

function addString($text, $add, $type = 'prepend') {
   // oneliner here
   return $text;
}

$text = 'World';
addString($text, 'Hello ', 'prepend'); // returns 'Hello World'
addString($text, ' Hello', 'append'); // returns 'World Hello'

Any ideas? : )

What about this, using the ternary ?: operator :

function addString($text, $add, $type = 'prepend') {
   return $type=='prepend' ? $add . $text : $text . $add;
}

Note : I actually would probably not use that -- and stay with a classic if/else : not a one-liner, not as nice to read... But probably a lot easier to understand ; and having understandable code is what trully matters.

Edit after the comment : if you want to make sure that the $type is either 'append' or 'prepend', and still want a one-liner, you could go with something like this :

function addString($text, $add, $type = 'prepend') {
   return ($type=='prepend' ? $add . $text : ($type=='append' ? $text . $add : ''));
}

But your code will become harder to read -- and it's probably time to go with something that's longer than just one line of code, and easier to understand.

For example, why not something like this :

function addString($text, $add, $type = 'prepend') {
    if ($type === 'prepend') {
        return $add . $text;
    } else if ($type === 'append') {
        return $text . $add;
    } else {
        // Do some kind of error-handling
        // like throwing an exception, for instance
    }
}

After all, the number of lines has pretty much no impact on the way the code is executed -- and, again, what matters is that your code is easy to understand and maintain.

return $type == 'prepend' ? $add . $text : $text . $add;

Are you familiar with the . in PHP?

For example:

echo $text . "Hello!";

http://www.phpf1.com/tutorial/php-string-concatenation.html

You could use a ternary operator to achieve this as follows:

function addString($text, $add, $type = 'prepend') {
   return $type == 'prepend' ? $add . $text : $text . $add;
}

What the ternary operator is effectively doing is checking the first condition (the one prior to the ? to see if it evaluates to true. If it does, it sets the return value of the statement to $add . $text, if not if uses the final block (after the :) to set the return value to $text . $add.

As the PHP manual puts it:

The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1 evaluates to TRUE, and expr3 if expr1 evaluates to FALSE.

As such, if someone provides something other than 'prepend' as the $type argument's value, then this will always default to the second condition and append.

$text = ($type === 'prepend') ? $add.$text : $text.$add;