Lesson 1 php syntax
- 1. Welcome to Computer Programmer 2 PHP Language – Lesson 1 Prepared By: Analyn G. Regaton
- 2. PHP Installation 1. Download and install sublime text – compiler /editor 2. Download and install wamp server – to support php file, database and also apache.
- 3. PHP SYNTAX (Basic) A PHP script can be placed anywhere in the document. A PHP script starts with <?php and ends with ?>: The default file extension for PHP files is ".php". A PHP file normally contains HTML tags, and some PHP scripting code. Note: PHP statements end with a semicolon (;).
- 4. PHP Case Sensitivity In PHP, keywords (e.g. if, else, while, echo, etc.), classes, functions, and user-defined functions are not case-sensitive. In the example below, all three echo statements below are equal and legal: Note: However; all variable names are case- sensitive!
- 5. PHP Case Sensitivity Look at the example in the left side; only the first statement will display the value of the $color variable! This is because $color, $COLOR, and $coLOR are treated as three different variables: result
- 6. Comments in PHP A comment in PHP code is a line that is not executed as a part of the program. Its only purpose is to be read by someone who is looking at the code. Comments can be used to: •Let others understand your code •Remind yourself of what you did - Most programmers have experienced coming back to their own work a year or two later and having to re-figure out what they did. Comments can remind you of what you were thinking when you wrote the code
- 8. PHP Variables Variables are "containers" for storing information. Creating (Declaring) PHP Variables In PHP, a variable starts with the $ sign, followed by the name of the variable: After the execution of the statements in the left, the variable $txt will hold the value Hello world!, the variable $x will hold the value 5, and the variable $y will hold the value 10.5. Note: When you assign a text value to a variable, put quotes around the value. Note: Unlike other programming languages, PHP has no command for declaring a variable. It is created the moment you first assign a value to it.
- 9. PHP Variables Rules for PHP variables: •A variable starts with the $ sign, followed by the name of the variable •A variable name must start with a letter or the underscore character •A variable name cannot start with a number •A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ) •Variable names are case-sensitive ($age and $AGE are two different variables)
- 10. PHP Variables Output Variables The PHP echo statement is often used to output data to the screen. The following example will show how to output text and a variable: result result
- 11. PHP Variables PHP Variables Scope In PHP, variables can be declared anywhere in the script. The scope of a variable is the part of the script where the variable can be referenced/used. PHP has three different variable scopes: •local •global •static Global and Local Scope A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function: result
- 12. PHP Variables A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function: Global and Local Scope result
- 13. PHP Variables PHP The global Keyword The global keyword is used to access a global variable from within a function. To do this, use the global keyword before the variables (inside the function): result
- 14. PHP Variables PHP The static Keyword Normally, when a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. We need it for a further job. To do this, use the static keyword when you first declare the variable: result
- 15. PHP echo and print Statements With PHP, there are two basic ways to get output: echo and print. echo and print are more or less the same. They are both used to output data to the screen. The differences are small: echo has no return value while print has a return value of 1 so it can be used in expressions. echo can take multiple parameters (although such usage is rare) while print can take one argument. echo is marginally faster than print. The PHP echo Statement The echo statement can be used with or without parentheses: echo or echo(). result Display Text
- 16. PHP echo and print Statements Display Variables The following example shows how to output text and variables with the echo statement: result
- 17. PHP echo and print Statements The PHP print Statement The print statement can be used with or without parentheses: print or print(). Display Text The following example shows how to output text with the print command (notice that the text can contain HTML markup):
- 18. PHP echo and print Statements Display Variables The following example shows how to output text and variables with the print statement:
- 19. The end !