Podręcznik PHP
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# substr

(PHP 3, PHP 4, PHP 5)

substr -- Return part of a string

## Description

string substr ( string string, int start [, int length] )

substr() returns the portion of `string` specified by the `start` and `length` parameters.

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.

Przykład 1. Basic substr() 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 achived using "curly braces" $string = 'abcdef'; echo $string{0}; // a echo $string{3}; // d echo $string{strlen($string)-1}; // f ?>`

If `start` is negative, the returned string will start at the `start`'th character from the end of `string`.

Przykład 2. 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 `string` is less than or equal to `start` characters long, `FALSE` will be returned.

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 a position beyond this truncation, an empty string will be returned.

Przykład 3. 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 "" $rest = substr("abcdef", -3, -1); // returns "de" ?>`

See also strrchr(), substr_replace(), preg_match(), trim(), mb_substr() and wordwrap().

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substr_replace | Początek rozdziału | trim