Returns the portion of string
specified by the start
and length
parameters.
The input string. Must be one character or longer.
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 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" ?>
If length
is given and is positive, the string returned will contain at most length
characters beginning from start
(depending 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 truncation 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" ?>
Returns the extracted part of string
; or FALSE
on failure, or an empty string.
Returns FALSE
on error.
If string
is equal to start
characters long, an empty string will be returned. Prior to this version, FALSE
was returned in this case.
If the start
parameter indicates the position of a negative truncation or beyond, false is returned. Other versions get the string from start.
<?php $rest = substr("abcdef", -1); // returns "f" $rest = substr("abcdef", -2); // returns "ef" $rest = substr("abcdef", -3, 1); // returns "d" ?>
<?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" ?>
<?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 ?>
<?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; ?>
Output of the above example in PHP 7:
1) 'pe' 2) '54' 3) 'gr' 4) '1' 5) '' 6) '' 7) '1200'
Output of the above example in PHP 5:
1) 'pe' 2) '54' 3) 'gr' 4) '1' 5) false 6) false 7) '1200'
<?php var_dump(substr('a', 2)); // bool(false) ?>
trim() -
Please login to continue.