docs:tips_n_tricks:php.html
This is an old revision of the document!
PHP
Meaning of isset() and empty()
<? print '| $foobar '; $foobar = NULL; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n"; print '| $foobar = 0 '; $foobar = 0; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n"; print '| $foobar = "" '; $foobar = ""; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n";
print '| $foobar = 42 '; $foobar = 42; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n"; print '| $foobar = "42"'; $foobar = "42"; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n"; print '| $foobar = "x" '; $foobar = "x"; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n"; print '| $foobar = NULL'; $foobar = NULL; if(isset($foobar)) print '| set ' ; else print '| not set ' ; if(empty($foobar)) print '| empty ' ; else print '| not empty ' ; print "|\n";
gives
| $foobar | not set | empty | | $foobar = 0 | set | empty | | $foobar = "" | set | empty | | $foobar = 42 | set | not empty | | $foobar = "42"| set | not empty | | $foobar = "x" | set | not empty | | $foobar = NULL| not set | empty |
docs/tips_n_tricks/php.html.1331196686.txt.gz · Last modified: 08.03.2012 09:51 CET by peter