What is the difference between function and method in php

A function is a piece of code that is called by name. It can be passed data to operate on (i.e. the parameters) and can optionally return data (the return value). All data that is passed to a function is explicitly passed.


A method is a piece of code that is called by a name that is associated with an object. In most respects it is identical to a function except for two key differences:

1. A method is implicitly passed the object on which it was called.
2. A method is able to operate on data that is contained within the class (remembering that an object is an instance of a class - the class is the definition, the object is an instance of that data).

Good practice of creating functions in PHP

Function names for user-level functions should be enclosed with in the PHP_FUNCTION() macro. They should be in lowercase, with words underscore delimited, with care taken to minimize the letter count.

Abbreviations should not be used when they greatly decrease the readability of the function name itself::

Good:

           'str_word_count'

           'array_key_exists'

Ok:

           'date_interval_create_from_date_string'

           (could be 'date_intvl_create_from_date_str'?)

           'get_html_translation_table'

           (could be 'html_get_trans_table'?)

Bad:

           'hw_GetObjectByQueryCollObj'

           'pg_setclientencoding'

           'jf_n_s_i'

Good practice of creating methods in PHP

Method names follow the 'studlyCaps' (also referred to as 'bumpy case' or 'camel caps') naming convention, with care taken to minimize the letter count. The initial letter of the name is lowercase, and each letter that starts a new 'word' is capitalized::

Good:
           'connect()'
           'getData()'
           'buildSomeWidget()'

Bad:
           'get_Data()'
           'buildsomewidget'
           'getI()'