2. Content:
1. String Variable
2. Concatenate Operators
3. String with Single and Double
Quote
4. String with heredoc
5. The PHP strlen() function
6. The PHP strpos() function
7. The str_replace function
8. The strtoupper() function
9. The ucfirst() function
10. The trim() function 2
11. The strtolower() function
3. 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
4. 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
5. String with Single and Double
quote
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);
6. 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
7. 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 />
8. 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
9. 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).
10. 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 .
11. 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.
12. The strtoupper() Function
The strtoupper() function is used to convert all
lowercase of the string word or sentence to
uppercase.
example
<?php
$str=‚start your first php with
w3school.‛;
echo strtoupper($str);
?>
Here is the result
START YOUR FIRST PHP WITH
W3SCHOOL.
12
13. 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
14. 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
15. 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
