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        php 为空时为空?

        php is null when empty?(php 为空时为空?)
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                  问题描述

                  I have a question regarding NULL in PHP:

                    $a = '';
                    if($a == NULL) {
                        echo 'is null';
                    }
                  

                  Why do I see is null when $a is an empty string? Is that a bug?

                  解决方案

                  What you're looking for is:

                  if($variable === NULL) {...}
                  

                  Note the ===.
                  When use ==, as you did, PHP treats NULL, false, 0, the empty string, and empty arrays as equal.

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