PHP has a great number of mathematical functions ready for you to use, as well as several constants for popular numbers so you do not have to calculate them yourself.
Nearly all of the functions can be grouped into three areas: rounding, randomisation, and conversion. Naturally some of these functions are only useful to people with a specific interest in mathematics, but, happily, the majority of these functions come into the conversion group.
Next chapter: Rounding >>
Converting from components
Functions Functions overview How to read function prototypes Working with variables Controlling script execution Working with Date and Time Reading the current time Converting from a string Converting to a string Converting from components Mathematics Rounding Randomisation Trigonometrical conversion Other mathematical conversion functions Base conversion Mathematical constants Playing with strings Reading from part of a string Replacing parts of a string Converting to and from ASCII Measuring strings Finding a string within a string Returning the first occurrence of a string Trimming whitespace Wrapping your lines Changing string case Making a secure data hash Alternative data hashing Automatically escaping strings Pretty-printing numbers Removing HTML from a string Comparing strings Padding out a string Complex string printing Parsing a string into variables Regular expressions Basic regexes with preg_match() and preg_match_all() Novice regexes Advanced regexes Guru regexes Regular expression replacements Regular expression syntax examples A regular expression assistant Checking whether a function is available Extension functions Pausing script execution Executing external programs Connection-related functions Altering the execution environment User functions Return values Parameters Passing by reference Returning by reference Default parameters Variable parameter counts Variable scope in functions Overriding scope with the GLOBALS array Recursive functions Variable functions Callback functions The declare() function and ticks Handling non-English characters Undocumented functions Summary Exercises Further reading Next chapter
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