String Functions

Strings are sequences of characters. They are useful for storing data and also for accepting user input, whether it be from a terminal command line or a web form.

I find these particular string functions indispensable in my own web programming. I'm sure there are many other frequently-used string functions.

Action	C++	PHP	JavaScript
Split a string into an array of strings	–	explode	split
Compare strings	compare	strcmp	< or >
Find a character within a string	find	strchr	indexOf
Get length of string	size	strlen	length
Find a string within a string	strstr	strstr	indexOf
Convert a string to hexadecimal	std::hex	–	toString(16)
Get a substring	substr	substr	substring
Convert string to floating point	atof	floatval	parseFloat
Convert string to integer	atoi	intval	parseInt
Upper case first character	toupper	ucfirst	toUpperCase
Trim white space	–	trim	trim
Replace	replace	str_replace	replace
Regular expression replace	c	preg_replace	replace
Determine if string is a number	–	is_numeric	!isNan

There are also a few useful functions that relate to single characters only, but they are usually used in the context of string processing.

Action	C++	PHP	JavaScript
Get the ASCII value of a character	–	chr	fromCharCode
Determine if character is a digit	isdigit	ctype_digit	parseInt and slice
Determine if a character is upper case	isupper	ctype_upper	compare with toUpperCase