Home > Article > Backend Development > How to replace the penultimate character in a string in php
In PHP, you can use the substr_replace() function to replace the penultimate character of the string; this function can replace the specified number of characters starting from the specified position in the string, and only needs to pass the third parameter Set to "-2", and the fourth parameter is set to 1 to replace the penultimate character. The syntax is "substr_replace(string, replacement value,-2,1)".
The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer
How to replace the penultimate digit of a string in php character? Simple, just use the substr_replace() function.
The substr_replace() function can replace the specified number of characters starting from the specified position in the string.
This function accepts 4 parameters, syntax:
substr_replace(string,replacement,start,length)
| Parameters | Description |
|---|---|
| string | Required. Specifies the string to check. |
| replacement | Required. Specifies the string to be inserted. |
| start | Required. Specifies where in the string to begin replacement.
|
| length | Optional. Specifies how many characters to replace. The default is the same as the string length.
|
#If start is a positive number, replacement will start from the start position of string. If start is negative, the replacement will start at the start position from the bottom of string.
If the length parameter is set and is a positive number, it represents the length of the replaced substring in string. If set to a negative number, it represents the number of characters from the end of the substring to be replaced from the end of string. If this parameter is not provided, the default is strlen(string) (the length of the string). Of course, if length is 0, then the function of this function is to insert replacement at the start position of string.
If you want to replace the penultimate character of the string, you only need to set the third parameter to "-2" and the fourth parameter to 1.
Example:
"; $replace = 'A'; echo "替换倒数第二个字符后：".substr_replace($str, $replace, -2,1); ?>
Recommended learning: "PHP Video Tutorial"
The above is the detailed content of How to replace the penultimate character in a string in php. For more information, please follow other related articles on the PHP Chinese website!