3

suppose 

$test = '';

if(empty($test)){ $test = "not found";}

echo $test;

the above case the answer will be "not found"

but below one even though the $test variable is empty but result give nothing.

$test = ' ';

if(empty($test)){ $test = "not found";}

echo $test;

how we can treat both these variables as empty in PHP??

tereško
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alwyn
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    A string is empty if its length is 0. A string with a single space character has the length 1. – Gumbo May 09 '11 at 17:27

5 Answers5

8

$test = ' ' is not empty. From the details in the documentation:

The following things are considered to be empty:

  • "" (an empty string)
  • 0 (0 as an integer)
  • 0.0 (0 as a float)
  • "0" (0 as a string)
  • NULL
  • FALSE
  • array() (an empty array)
  • var $var; (a variable declared, but without a value in a class)

If you want to test if $test is only white space characters, see these questions:

If string only contains spaces?
How to check if there are only spaces in string in PHP?

Community
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Paul DelRe
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6

Trim the value before checking it.

It is important to trim before checking it because empty only checks variables and not the value you're passing in.

$test = trim(' ');

if (empty($test)) { /* ... */ }

echo $test;
pickypg
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1

You could do if (empty(trim($test))) ...

CORRECTED:

$test = trim($test);

if (empty($test)) ...

Trim removes whitespace from both sides of a string.

Austin
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  • -1 because `empty` only works on variables, not on expressions. This case is explicitly mentioned in the PHP manual that it will *not* work. – Sander Marechal May 09 '11 at 17:28
1

I have no idea why everybody is recommending empty here. Then you could just leave it out and use PHPs boolean context handling:

if (!trim($test)) {

But to actually check if there is any string content use:

if (!strlen(trim($test))) {
mario
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0

Create your own function to test this:

function my_empty($str) {
  $str = trim($str);
  return empty($str);
}

That will treat all strings containing only whitespace as empty, in addition to whatever the empty method already provides.

Thilo
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