Mastering Strings and Arrays in PHP

1. Post-Module PHP Introduction BTM 395: Internet Programming

2. PHP string quoting • ' (single quote): for literal strings with minimal text expansion (\\ and \' only) • " (double quote): for flexible strings with expansion of variables and many codes (e.g. \n and \t) • Heredoc: for lengthy strings with complex plain-text format (see http://codepad.org/pzHHK3wH) • Begins with <<<ANY_DELIMITER • Ends with ANY_DELIMITER; as the only contents of closing line • Expands variables similarly to " • Advantage: no need to escape ' or " • Nowdocformat works like single quote equivalent of heredoc • Official reference: http://php.net/manual/en/language.types.string.php

3. Array indexing • ALL arrays in PHP are associative arrays • Numeric indices are automatically generated, but the arrays are still fully associative • Arrays can have both flexible associative keys and auto-generated numeric keys • Official reference: http://www.php.net/manual/en/language.types.array.php

4. Customized array sorting • PHP has many built in array sort functions, for sorting by value, by key, and backwards • JavaScript only has one very limited built-in sort: lexicographic (strict alphabetic) sort • Both have custom sort functions that work similarly • JavaScript: myArray.sort(function(a,b){…}); • PHP: usort($myArray,customSortFunction);customSortFunction(a,b){…}; • These can sort any kind of array anyway you like, including multidimensional arrays

5. Other PHP tips • Equality and assignment = vs == vs === • The ternary (conditional) operator ? : • $myVar = $testCondition? $valueIfTrue: $valueIfFalse; • Ternary operator exercise • Stop an infinite loop in PHP • Click the stop or cancel button on your browser to stop the page loading • Or just wait 30 seconds or so for a server timeout

6. Sources • Heredoc example: http://www.tuxradar.com/practicalphp/2/6/3