Published Jul 4, 2023
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The stripos() function performs a case-insensitive search for the position of the first occurrence of a substring in a given string. If the substring is found, it will return the index of the beginning of the substring. If it isn’t found, the function won’t return any output.

stripos() is binary-safe, meaning it will interpret the string with the correct amount of characters it contains, even if the string contains non-ASCII bytes or null bytes.


stripos(given_string, sub_string_to_find, start_search)

Required Parameters:

  • given_string is the string that the function searches.
  • sub_string_to_find is the value to search for within given_string.

Optional Parameters:

  • start_search tells the function to start the search at a specified index.

Note: If the substring is not found the method will not return anything, but will evaluate to false.


With Required Parameters

echo stripos("I will return the position of a string", "will");

Note: String positions start at index 0.

The output of the above code will be 2, as the string “will” starts at index 2.

stripos() is case-insensitive. In the example above, the result would be the same if the second parameter was written as “WILL” instead of “will”.


With Required and Optional Parameters

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The above code is runnable, alter the start_search parameter to see how it changes the result.

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