Introduction to PHP for Os X by Example
Text, Numbers & Variables
- Basic variables in PHP can contain strings or numbers.
- Variable names should start with $ and contain only alphanumeric characters and underscores. They should not start with a number.
- PHP makes a distinction between integers and floating-point numbers when storing them internally. Floating point numbers may be stored inaccurately.
- Use a single period to concatenate strings.
- The print() language construct is used to output data to the browser window.
- Single quoted strings can not interpolate variables (see below) and to use single quotes or back slashes in them they must be escaped using a back slash.
- Using double-quotes instead of single-quotes we can take advantage of interpolation.
- The concatenation operator in conjunction with the assignment operator (.=) appends a string to a string.
- The arithmetic operators perform arithmetic operations (+, -, *, /, %, ++, –).
- Arithmetic operators in conjunction with the assignment operator (+=) perform the arithmetic operation on the left hand variable with the right-hand variable.
e.g. $n = 2; $n += 2; $n is now 4.
- We can convert strings to numbers and vice-versa by using the appropriate operators (period for strings, plus sign for numbers).
- The printf() function can be used to control the formatting of print output.
- Here document syntax can be used to print out large blocks of data and does not require double quotes to be escaped.
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