Content:1. String Variable2. Concatenate Operators3. String with Single and DoubleQuote4. String with heredoc5. The PHP strlen() function6. The PHP strpos() function7. The str_replace function8. The strtoupper() function9. The ucfirst() function10. The trim() function 211. The strtolower() function
String Variable String variables are used for values that contain characters. After we have created a string variable we can manipulate it. A string can be used directly in a function or it can be stored in a variable. Here is PHP script with string value <?php $str=‚This is String in PHP.‛; echo $str; ?> Output of the above script are: This is string in PHP 3
The PHP Concatenation Operator There is only one string operator in PHP. The concatenation operator (.) is used to join two string values together. Below is the example of string concatenation <?php $txt1="Hello world!"; $txt2="What a nice day!"; echo $txt1 . " " . $txt2; ?> The result of the above Hello world What a nice day! 4
String with Single and Doublequote There are two way when you can specify a string in php single quote and double quote. Single quoted strings are treated almost literally. double quoted strings replace variables with their values as well as specially interpreting certain character sequences. Here is an example <?php $variable=‚name‛; $literally=‘My $variable will not print n’; print($literally); $literally=‚My $variable will print n‛; 5 print($literally);
The result of the above code will be My $variable will not print!n My name will print String with double quote will process in both two way: 1. Certain character sequences beginning with backslash () are replaced with special characters 2. Variable names (starting with $) are replaced with string representations of their values. The escape-sequence replacements are: n is replaced by the newline character r is replaced by the carriage-return character t is replaced by the tab character $ is replaced by the dollar sign itself ($) " is replaced by a single double-quote (") is replaced by a single backslash () 6
String with Heredoc You can assign multiple lines to a single string variable using heredoc . See the example below <?php echo <<<END This uses the "here document" syntax to output multiple lines with variable interpolation. Note that the here document terminator must appear on a line with just a semicolon. no extra whitespace! 7 <br />
In code above after heredoc must be follow by some identifier for example END and must be end with the same identifier as the start one with semiconlon sign Even though using heredoc is difficult and can Couse some problem. Note that the closing sequence END; must occur on a line by itself and cannot be indented. 8
The PHP strlen() Function Strlen() function used to return the length of the string example: <?php $str=‚Welcome back to PHP‛; echo strlen($str); ?> Result will be 19 The length of a string is often used in loops or other functions, when it is important to know when the string ends. (i.e. in a loop, we would want to stop 9 the loop after the last character in the string).
The strops() Function Strpos() function is used to return the search of character with in the string. If match is found, function will return the position of the first character of the match word. example: <?php echo strpos(‛Welcome back to PHP‛,‛PHP‛); ?> The result of the above script is follow 16 The resean is that it return only the first 10 character of the whole word .
The str_replace function The str_replace function is use to search and replace the search result with the new word. If no word match it will return the original word. example <?php $str=‚Welcome back to PHP.‛; echo str_replace(‚PHP‛,‛PHP Function‛,$str); ?> This will search for the word PHP and replace with the word PHP Function. The result is: 11 Welcome back to PHP Function.
The strtoupper() Function The strtoupper() function is used to convert all lowercase of the string word or sentence to uppercase. example <?php $str=‚start your first php withw3school.‛; echo strtoupper($str); ?> Here is the result START YOUR FIRST PHP WITH W3SCHOOL. 12
The strtolower() Function The strtolower() function is used to convert all uppercase string to lowercase. example <?php $str=‚START YOUR FIRST PHP WITH W3SCHOOL.‛; echo strtolower($str); ?> Here is the result start your first php with w3school. 13
The ucfirst() function Ucfirst() function used to capital the first letter of the first word in the whole string. example <?php $str=‚using ucfirst() function.‛; echo($str); ?> The result is Using ucfirst() function. 14
The trim() function Trim() function strip a string of white space in front and at the end of the whole string. example <?php $str=‚ Welcome! ‛; echo($str); ?> The above will result as below Welcome! 15