(PHP 4 >= 4.3.0, PHP 5, PHP 7) Calculate the sha1 hash of a string

(PHP 4, PHP 5, PHP 7) Make a string lowercase

(PHP 4 >= 4.0.5, PHP 5, PHP 7) Get numeric formatting information

(PHP 4, PHP 5, PHP 7) Binary safe case-insensitive string comparison

(PHP 4, PHP 5, PHP 7) Find the first occurrence of a string

(PHP 4 >= 4.0.1, PHP 5, PHP 7) Pad a string to a certain length with another string

(PHP 5 >= 5.3.0, PHP 7) Parse a CSV string into an array

(PHP 4, PHP 5, PHP 7) Format a number with grouped thousands

(PHP 5, PHP 7) Write a formatted string to a stream

(PHP 4, PHP 5, PHP 7) Reverse a string string