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"if" for time
02-06-2004
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SUBSTR(3) 1 SUBSTR(3) substr - Return part of a string SYNOPSIS
string substr (string $string, int $start, [int $length]) DESCRIPTION
Returns the portion of $string specified by the $start and $length parameters. PARAMETERS
o $string - The input string. Must be one character or longer. o $start - If $start is non-negative, the returned string will start at the $start'th position in $string, counting from zero. For instance, in the string ' abcdef', the character at position 0 is ' a', the character at position 2 is ' c', and so forth. If $start is negative, the returned string will start at the $start'th character from the end of $string. If $string is less than or equal to $start characters long, FALSE will be returned. Example #1 Using a negative $start <?php $rest = substr("abcdef", -1); // returns "f" $rest = substr("abcdef", -2); // returns "ef" $rest = substr("abcdef", -3, 1); // returns "d" ?> o $length - If $length is given and is positive, the string returned will contain at most $length characters beginning from $start (depend- ing on the length of $string). If $length is given and is negative, then that many characters will be omitted from the end of $string (after the start position has been calculated when a $start is negative). If $start denotes the position of this trunca- tion or beyond, false will be returned. If $length is given and is 0, FALSE or NULL, an empty string will be returned. If $length is omitted, the substring starting from $start until the end of the string will be returned. Example #2 Using a negative $length <?php $rest = substr("abcdef", 0, -1); // returns "abcde" $rest = substr("abcdef", 2, -1); // returns "cde" $rest = substr("abcdef", 4, -4); // returns false $rest = substr("abcdef", -3, -1); // returns "de" ?> RETURN VALUES
Returns the extracted part of $string; or FALSE on failure, or an empty string. CHANGELOG
+--------------+---------------------------------------------------+ | Version | | | | | | | Description | | | | +--------------+---------------------------------------------------+ |5.2.2 - 5.2.6 | | | | | | | If the $start parameter indicates the position | | | of a negative truncation or beyond, false is | | | returned. Other versions get the string from | | | start. | | | | +--------------+---------------------------------------------------+ EXAMPLES
Example #3 Basic substr(3) usage <?php echo substr('abcdef', 1); // bcdef echo substr('abcdef', 1, 3); // bcd echo substr('abcdef', 0, 4); // abcd echo substr('abcdef', 0, 8); // abcdef echo substr('abcdef', -1, 1); // f // Accessing single characters in a string // can also be achieved using "square brackets" $string = 'abcdef'; echo $string[0]; // a echo $string[3]; // d echo $string[strlen($string)-1]; // f ?> Example #4 substr(3) casting behaviour <?php class apple { public function __toString() { return "green"; } } echo "1) ".var_export(substr("pear", 0, 2), true).PHP_EOL; echo "2) ".var_export(substr(54321, 0, 2), true).PHP_EOL; echo "3) ".var_export(substr(new apple(), 0, 2), true).PHP_EOL; echo "4) ".var_export(substr(true, 0, 1), true).PHP_EOL; echo "5) ".var_export(substr(false, 0, 1), true).PHP_EOL; echo "6) ".var_export(substr("", 0, 1), true).PHP_EOL; echo "7) ".var_export(substr(1.2e3, 0, 4), true).PHP_EOL; ?> The above example will output: 1) 'pe' 2) '54' 3) 'gr' 4) '1' 5) false 6) false 7) '1200' ERRORS
/EXCEPTIONS Returns FALSE on error. Example #5 <?php var_dump(substr('a', 1)); // bool(false) ?> SEE ALSO
strrchr(3), substr_replace(3), preg_match(3), trim(3), mb_substr(3), wordwrap(3), String access and modification by character. PHP Documentation Group SUBSTR(3)