PHP If Statement

Programs constantly have to make decisions: if the user is logged in, show one thing; if not, show another. Conditional statements are how you tell PHP to choose between different actions.

PHP gives you these options:

• if statement - runs a piece of code only when a condition is true
• if...else statement - runs one piece of code when a condition is true and a different piece when it is false
• if...elseif...else statement - chooses between different pieces of code when there are more than two conditions
• switch statement - picks one block out of many to run

The simplest decision is an if: when its condition is true, the code inside the braces runs, and otherwise PHP skips it.

Since 5 is greater than 3, the condition is true and the message is displayed:

An if statement is written like this:

Indenting the code inside an if block is optional as far as PHP is concerned. Do it anyway, since it is considered good practice and makes the structure much easier to read.

The echo line below is indented to show that it belongs to the if block:

A single if can test several conditions at once. Join them with the && or || operators, and add as many as you need:

Both checks have to pass here: $a must be above $b and, at the same time, below $c:

One passing check is enough with OR. Here $a would need to be 2 or 3, but it is 5, so the else block runs: