PHP strspn() Function (original) (raw)
Last Updated : 22 Jun, 2023
The strspn() function is an in-built function in PHP which finds the length of the initial segment of a string consisting entirely of characters contained within a given list of characters passed as a parameter to the function.
Syntax :
strspn( string,string, string,charlist, start,start, start,length)
Parameters : This function accepts four parameters as shown in the above syntax. First two parameters are mandatory and must be supplied while the remaining two parameters are optional. All of these parameters are described below:
- $string : This mandatory parameter specifies the string to search.
- $charlist : This mandatory parameter specifies the list of characters to be searched in the given $string.
- $start : This optional parameter specifies the index from where we want to start searching in the string.
- If $start is given and is non-negative, then strspn() will begin examining $string from that position.
- If $start is given and is negative, then strspn() will begin examining stringfromthatpositionfromtheendofstring from that position from the end of stringfromthatpositionfromtheendofstring.
- $length : It specifies the number of characters of stringwhichareneededtobesearched.Itsdefaultvalueistilltheendofthestring which are needed to be searched. Its default value is till the end of the stringwhichareneededtobesearched.Itsdefaultvalueistilltheendofthestring.
- If $length is given and is non-negative, then stringwillbeexaminedforstring will be examined for stringwillbeexaminedforlength characters from the starting position.
- If $length is given and is negative, then stringwillbeexaminedfromthestartingpositionuptostring will be examined from the starting position up to stringwillbeexaminedfromthestartingpositionuptolength characters from the end of $string.
Return Value: This function returns the number of characters found in the string that contains only characters from the charlist parameter.
Examples:
Input : string="abcdefghijk",string = "abcdefghijk", string="abcdefghijk",charlist = "abcjkl" Output : 3
Input : string="GeeksforGeeks",string = "Geeks for Geeks", string="GeeksforGeeks",charlist = "Geeksfor " Output : 15
Below programs illustrate the strspn() function:
Program 1:
<?php
echo strspn ( "Geeks for Geeks" , "Geeksfor " );
?>
Output:
15
Program 2: This program illustrates the case-sensitivity of strspn() function.
<?php
echo strspn ( "Geeks for Geeks" , "geeks" );
?>
Output:
0
Program 3: This program illustrates the use of strspn() function with startandstart and startandlength parameters.
<?php
echo strspn ( "Geeks for Geeks" , " for" , 5, 9);
?>
Output:
5
Program 4: This program illustrates the use of strspn() function with negative $length parameter.
<?php
echo strspn ( "Geeks for Geeks" , " for" , 5, -5);
?>
Output:
5
Program 5: This program illustrates the use of strspn() function with a negative $start parameter.
<?php
echo strspn ( "Geeks for Geeks" , "for" , -5);
?>
Output:
0