PHP String substr_replace() Function
The substr_replace is an in-built function of PHP, which replaces a part of the string with another text within a string. PHP 4+ versions support this function. The index in the original string is passed as a parameter to which the replacement is to be performed. An array of string can also be passed as a parameter to this function, and in that case, a replacement will be done for each string at every turn (See Example 5).
Note: The substr_replace() is a binary-safe function.
The syntax for the substr_replace() is given below, which accepts four arguments.
The substr_replace() consists of four parameters, in which three parameters are mandatory to pass in this function whereas $length parameter is optional. All these parameters are discussed below in detail:
$string (required) - It is the main string parameter of this function, which specifies the input string in which the replacement will be done. This is a mandatory parameter.
$replacement (required) - It is a mandatory parameter of the substr_replace(), which specifies the string to insert. The $replacement contains the string to which the replacement is going to be done.
$start (required) - It is also a mandatory parameter, which specifies the position from where the replacement needs to be started. This parameter holds the integer value. There are three conditions for this parameter:
$length (optional) - It is an optional parameter of this function, which specifies how many characters, are to be replaced in the string. In case $length parameter is not passed in substr_replace(), then replacement stops at the end of the string. There are also three conditions for this parameter:
The substr_raplace() returns a string after the replacement is done. In case, if the string is an array, then it returns an array.
From PHP 4.3.3, all the parameters accept arrays.
There are a few numbers of examples given, by which we can learn the practical implementation of the substr_replace() function.
In the above example, replacement is started from 6th position. "earth" is replaced with "javatpoint".
In the above example, replacement is started from 6th position in the first case. In the second case, a negative value is passed, so replacement is done at the end from 10th position in the string.
Hello PHP Hello PHP
In the above example, we have used the fourth $length parameter, whose value is passed 0. Hence the insertion of string "Hello" is done rather than replacement.
Welcome to javatpoint
Example 5: Replacement multiple strings at once
X: BBBB; Y: BBBB; Z: BBBB X: XXXX; Y: YYYY; Z: ZZZZ X: XXXXAA; Y: YYYYA; Z: ZZZZ
Note: Implode() function is used here for the array to string conversion.