Tutorial by Examples



Variables can be accessed via dynamic variable names. The name of a variable can be stored in another variable, allowing it to be accessed dynamically. Such variables are known as variable variables. To turn a variable into a variable variable, you put an extra $ put in front of your variable. $va...
There are different data types for different purposes. PHP does not have explicit type definitions, but the type of a variable is determined by the type of the value that is assigned, or by the type that it is casted to. This is a brief overview about the types, for a detailed documentation and exam...
We can illustrate this problem with the following pseudo-code function foo() { global $bob; $bob->doSomething(); } Your first question here is an obvious one Where did $bob come from? Are you confused? Good. You've just learned why globals are confusing and considered a bad p...
get_defined_vars() returns an array with all the names and values of the variables defined in the scope in which the function is called. If you want to print data you can use standard functions for outputting human-readable data, like print_r or var_dump. var_dump(get_defined_vars()); Note: This...
Although not necessary in PHP however it is a very good practice to initialize variables. Uninitialized variables have a default value of their type depending on the context in which they are used: Unset AND unreferenced var_dump($unset_var); // outputs NULL Boolean echo($unset_bool ? "tr...
In PHP, variable values have an associated "truthiness" so even non-boolean values will equate to true or false. This allows any variable to be used in a conditional block, e.g. if ($var == true) { /* explicit version */ } if ($var) { /* $var == true is implicit */ } Here are some fun...

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