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PHP Tutorial: Learn About PHP Function Syntax and its Parameters

Updated on November 9, 2011


In this PHP Tutorial, I'll explain some of the basics about PHP function Syntax (or I say syntax of PHP function), The Knowledge of which one should have in understanding it without any confusion. My Purpose of writing this article is to create a dedicated page on this topic, so, I could send visitors (Who are seeking this information) from my other PHP articles (Which are covering various segments of this programming language). Here, Below is the List of contents with anchor links pointing to various sections of this article, you can click on it to directly jump.

  1. What is Function Syntax ?,
  2. Syntax example of PHP Function,
  3. Understanding the Keyword used before Function Name,
  4. PHP Supported Data Types,
  5. Understanding the Keyword used before parameter Names or PHP Variables,
  6. Understanding the Usage of Square Brackets,
  7. Still Have Questions ???.

PHP Function SYntax
PHP Function SYntax

What is Function Syntax ?

Syntax of any function is just only a visual representation of it, which shows us,

  • What type (Data Type) of input are accepted as parameter values in corresponding function,
  • What type (Data Type) of output will be returned,
  • How many parameters are required at minimum by corresponding function,
  • How many Optional Parameters are supported by function,
  • What Kind of data each parameter should have in order to get relavance results.

Syntax Example of PHP Function

Here, Below is the Syntax of one well know PHP Core function, which simplifies our work of sending email from our scripts, If not blocked by webhost.

bool mail ( string $to 
		, string $subject 
		, string $message 
		[, string $additional_headers 
		[, string $additional_parameters 

Now, I will write other details while considering this function in Mind.

Understanding the Keyword used before Function Name

The Keyword "bool" used before function name tells us about the datatype of output returned by above function. It is Just only an identifier and is not required while working with actual function.

PHP supports eight primitive Data types, which are categorized into 4 types, See below.

Scalar Data Types

  • boolean,
  • integer,
  • float (floating-point number, aka double),
  • string,

Compound Types :

  • Array,
  • Object,

Special Types :

  • resource,
  • NULL,

Psudo-Types :

  • mixed,
  • number,
  • callback.

Understanding the Keyword used before Parameter Names

The Keyword "string" used before each parameter in function argument list are also identifiers and are not required while working with an actual function. The identifiers used before each parameter may or may not be same. This Keywords tells use about the datatype of each parameter value (Separately) that will be accepted by above function.

Understanding the Usage of Square Brackets.

Parameters specified in square brackets are optional/additional parameters (Arguments), which are supported by above function. These are used to extend capabilities of function. You can either supply values for them or not as per your needs.

Still Have Questions ???

If you have queries regarding this topic or any section of this article, then, You should post it in comments section below. I'll try my best to solve it but don't blame my English grammar (I'm still in learning phase).


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      Emmanuel 5 years ago

      Please I need a full tutorial on php and html..thanks

    • itech profile image

      Krishna 6 years ago from New Delhi, India

      Thanks for Commenting @mr-burns .

    • mr-burns profile image

      mr-burns 6 years ago

      A useful language to pick up. Thanks for the advice