Chapter - 7

String & Patterns( Built-in Function )

PHP: Hypertext Preprocessor

Outlineo What is String ?o Basic String o Using String As Arrayso Transforming Stringo Comparing Stringso Searching Stringso Matching Against Masko String Replace o Other String Functiono Arrays Functions

What is String ?

o A string is series of characters, where a character is

the same as a byte. This means that PHP only supports

a 256-character set, and hence does not offer native

Unicode support. See details of the string type.

o A string literal can be specified in four different ways:

single quoted

double quoted

heredoc syntax

nowdoc syntax (since PHP 5.3.0)

Basic Strings

String objects are a special type of container,

specifically designed to operate with sequences of

characters.

A string variable is used to store and manipulate

text.

String variables are used for values that contain

characters.

Basic Strings

We using the string to display some notation .

The string, like a variable, will have to be created first.

There are two ways to use a string in PHP - you can store it

in a function or in a variable. In the example below, we will

create a string twice - the first time storing it in a variable,

and the second time - in a function, in our case - an echo.

Basic Strings

<?php

$myString = "This is a string!";

echo "This is a string!";

echo $myString;

?>

 Use some different functions &

operators to manipulate the

string.

Using String As Arrays

You can access the individual characters of

a strings as if they were members of an

array.

$text = “abcdef”;a b c d e f

0 1 2 3 4 5

Characters

Index

Using String As Arrays

<?php

$str = “abcdef”;

echo $str[‘1’] ; // b

//Or

for($i =0 ;$i < srtlen($str); $i++)

{

echo $str[$i];

}

?>

String Function

In PHP we have tow type of functions :

1) User-defined Function.

2) Built-in Function.

User-defined Function : is the function created

by user .

Built-in Function : is the function created by

PHP , and ready to use.

The real power of PHP comes from its functions.

We just talk about Built-in Function in this

chapter

Transforming String

If given two arguments, the second should be

an array in the form array('from' => 'to', ...).

The return value is a string where all the

occurrences of the array keys have been replaced

by the corresponding values. The longest keys will

be tried first. Once a substring has been replaced,

its new value will not be searched again.

string strtr ( string $str , array $replace_pai

rs )

Transforming String

<?php

echo strtr("Hilla

Warld","ia","eo");

?> Output : Hello World

Transforming String

The strtr() If given three arguments, this function

returns a copy of str where all occurrences of

each (single-byte) character in from have been

translated to the corresponding character in to,

i.e., every occurrence of $from[$n] has been

replaced with $to[$n], where $n is a valid offset

in both arguments.;

string strtr ( string $str , string $from , stri

ng $to )

Transforming String

<?php

$arr = array("Hello" => "Hi", "world" =>

"earth");

echo strtr("Hello world",$arr);

?>

Output : Hi earth

Comparing Strings

You can comparison between strings by

more than one method ,the PHP when

comparison it make convert the data type

to other if the data type not the same.

Comparing Strings

<?php

If(“123aa” == 123)

{

echo “done”;

}

?>

Comparing Strings

This comparison is case sensitive.

Returns < 0 if str1 is less than str2; > 0

if str1 is greater than str2, and 0 if they

are equal.

int strcmp ( string $str1 , string $str2 )

Comparing Strings

<?php

echo strcmp("Hello world!","Hello

world!");

?>Output : 0

Comparing Strings

Binary safe case-insensitive string

comparison.

Returns < 0 if str1 is less than str2; > 0

if str1 is greater than str2, and 0 if they

are equal.

int strcasecmp ( string $str1 , string $str2 )

Comparing Strings

<?php

$var1 = "Hello";

$var2 = "hello";

if (strcasecmp($var1, $var2) == 0) {

    echo '$var1 is equal to $var2 in a case-

insensitive string comparison';

}

?>

Comparing Strings-example

<?php

$str = "Ali";

if(strcmp($str , "ali") == 0)

{

//we won't get here , becuse of case sensitivity

}

if(strcasecmp($str , "ali") == 0)

{

we well get here becuse strcasecmp() is case-insensitive

}

?>

Comparing Strings-example

<?php$st1 = “abcd1234”;$st2 = “abcd5678”;echo strncasecmp ($st1,$st2,4);

?>

Searching Strings

• Find the numeric position of the first occurrence

of needle in the haystack string.

• Returns the position of where the needle exists

relative to the beginning of the haystack string

(independent of offset). Also note that string

positions start at 0, and not 1.

• Returns FALSE if the needle was not found.

int strpos ( string $haystack ,  $needle [, int $offset = 0 ] )

Searching Strings

<?php

echo strpos("Hello world!","wo");

?>

Output : 6

Searching Strings-Example

<?php$str =“abcdef”;$se_str = “abc”;If(strpos($str,$se_srt) !== false){ echo “found”;}

?>

Searching Strings-Example

<?php$str ='1234567';$se_str = '123';echo strpos($str,$se_str,1); //false

?>

Searching Strings-Example

<?php$str ='123456';$se_str = ‘34';echo strtr($str,$se_str,1); // 3456

?>

Matching Against Mask

Finds the length of the initial segment of subject that

contains only characters from mask.

If start and length are omitted, then all of subject will be

examined. If they are included, then the effect will be the

same as callingstrspn(substr($subject, $start,

$length), $mask) (see substr for more information).

int strspn ( string $subject , string $mask [, int $start [, int $lengt

h ]] )

Matching Against Mask

<?phpecho strspn("Hello world!","kHlleo");

?>

Output : 5

Matching Against Mask

Returns the length of the initial segment

of str1 which does not contain any of the

characters in str2.

Returns the length of the initial segment

of subject which consists entirely of characters

in mask.

int strcspn ( string $str1 , string $str2 [, int $start [, int $length ]

] )

Matching Against Mask

<?php

echo strcspn("Hello world!","w");

?>

Output :

6

String Replace

This function returns a string or an array with all

occurrences of search in subject replaced with the

given replace value.

This function returns a string or an array with all occurrences of search in subject (ignoring case) replaced with the given replace value.

eplaces a copy of string delimited by the start and

(optionally) length parameters with the string given

inreplacement.

str_replace ( $search ,  $replace ,  $subject [, int &$count ] )

str_ireplace (  $search ,  $replace ,  $subject [, int &$count ]

)

substr_replace (  $string ,  $replacement ,  $start [,  $length

 ] )

String Replace-example

<?phpecho str_raplace(“Mr”,”Welcom”,”Mr

Ali”);

?>

Welcom Ali

String Replace -exmple

<?php$a = 0;echo str_raplace(“a”,”b”,”a1a1a1”,$a);echo $a // 3

?>

String Replace -exmple

<?phpecho substr_replace("welecom ali ","hi",7);

echo “<br>”;echo substr_replace("welecom my brother ali ","mr",9,10);

?> welecomhiwelecom mmrali

String Replace -exmple

<?php$str = “123456789”;echo substr($str,0,3);//123echo substr($str,1,1);//2echo substr($str,-2);//89echo substr($str,-2,1);//8

?>

String Functions

strtoupper() - Make a string uppercase

strtolower() - Make a string lowercase

ucfirst() - Make a string's first character

uppercase

ucwords() - Uppercase the first character

of each word in a string

strtoupper()

<?php$str = “make a string uppercase ";$str = strtoupper($str);echo $str;

?>

MAKE A STRING UPPERCASE

strtolower()

<?php$str = “MAKE A STRING LOWERCASE ";$str =  strtolower($str);echo $str;

?>

make a string lowercase

ucfirst()

<?php$str = “make a string's first character uppercase ";$str =  ucfirst($str);echo $str; 

?>

Make a string's first character uppercase

ucwords()

<?php$str = “uppercase the first character of each word in a string ";$str =  ucwords($str);echo $str; 

?>Uppercase The First Character Of Each Word In A

String

str_replace()

<?phpecho str_replace("world","Peter","Hello world!");

?>

Hello Peter!

str_replace()

<?php$arr = array("blue","red","green","yellow");print_r(str_replace("red","pink",$arr,$i));echo "Replacements: $i";

?>Array ( [0] => blue [1] => pink [2] => green [3] => yellow )

Replacements: 1

wordwrap()

Wraps a string to a given number of

characters using a string break character. Returns the given string wrapped at the

specified length.

wordwrap()

<?php$text="The quick brown fox jumped over t

he lazy dog.";echo wordwrap($text,20,"<br/> \n");?>

str_split ()

Converts a string to an array.

If the optional split_length parameter is specified, the

returned array will be broken down into chunks with each

being split_length in length, otherwise each chunk will be

one character in length.

FALSE is returned if split_length is less than 1. If

the split_length length exceeds the length of string, the

entire string is returned as the first (and only) array

element.

array str_split ( string $string [, int $split_lengt

h = 1 ] )

str_split ()

<?php

$str = "Hello Friend";

$arr1 = str_split($str);$arr2 = str_split($str, 3);

print_r($arr1);print_r($arr2);

?>

str_word_count()

Specify the return value of this function. The current

supported values are:

0 - returns the number of words found

1 - returns an array containing all the words found inside

the string

2 - returns an associative array, where the key is the

numeric position of the word inside the string and the

value is the actual word itself

 str_word_count ( string $string [, int $format =

0 [, string $charlist ]] )

str_word_count()

<?php

$str = "Hello fri3nd, you're       looking          good today!";

print_r(str_word_count($str, 1));print_r(str_word_count($str, 2));print_r(str_word_count($str, 1, 'àáãç3'));

echo str_word_count($str);

?>

explode ()

Returns an array of strings, each of which

is a substring of string formed by splitting

it on boundaries formed by the

string delimiter.

array explode ( string $delimiter , string $string [, int $limit ] )

explode ()

<?php

// Example 1

$chars  = “A B C D E F";

$pieces = explode(" ",  $chars);

echo $pieces[0]; // A

echo $pieces[1]; // B

?>

strrev() 

Returns string, reversed.<?php

echo strrev("Hello world!"); // outputs "!dlrow olle

?>

str_shuffle ()

shuffles a string. One permutation of all

possible is created.

str_shuffle ()

<?php$str = 'abcdef';$shuffled = str_shuffle($str);

// This will echo something like: bfdaececho $shuffled;

?>

rand ()

If called without the

optional min, max arguments rand() returns a

pseudo-random integer between 0

and getrandmax(). If you want a random number

between 5 and 15 (inclusive), for example,

use rand(5, 15)

int rand ( void )

int rand ( int $min , int $max )

rand ()

<?phpecho rand() . "\n";echo rand() . "\n";

echo rand(5, 15);?>

round ()

<?phpecho round(3.4);         // 3echo round(3.5);         // 4echo round(3.6);         // 4echo round(3.6, 0);      // 4echo round(1.95583, 2);  // 1.96echo round(1241757, -3); // 1242000echo round(5.045, 2);    // 5.05echo round(5.055, 2);    // 5.06

?>

round ( float $val [, int $precision = 0 [, int $mode = PHP_ROUND_HALF_UP ]] )

round ()

<?phpecho round(9.5, 0, PHP_ROUND_HALF_UP);   // 10echo round(9.5, 0, PHP_ROUND_HALF_DOWN); // 9echo round(9.5, 0, PHP_ROUND_HALF_EVEN); // 10echo round(9.5, 0, PHP_ROUND_HALF_ODD);  // 9

echo round(8.5, 0, PHP_ROUND_HALF_UP);   // 9echo round(8.5, 0, PHP_ROUND_HALF_DOWN); // 8echo round(8.5, 0, PHP_ROUND_HALF_EVEN); // 8echo round(8.5, 0, PHP_ROUND_HALF_ODD);  // 9

?>

max()

If the first and only parameter is an

array, max() returns the highest value in that

array. If at least two parameters are

provided, max()returns the biggest of these

values.

 max ( array $values )

 max (  $value1 ,  $value2 [,  $value3... ] )

max()

max() returns the numerically highest of the parameter

values. If multiple values can be considered of the same

size, the one that is listed first will be returned.

When max() is given multiple arrays, the longest array is

returned. If all the arrays have the same length, max() will

use lexicographic ordering to find the return value.

When given a string it will be cast as an integer when

comparing.

max()

<?phpecho max(1, 3, 5, 6, 7);  // 7echo max(array(2, 4, 5)); // 5

echo max(0, 'hello');     // 0echo max('hello', 0);     // hello

echo max('42', 3); // '42'

echo max(-1, 'hello');    // hello

$val = max(array(2, 2, 2), array(1, 1, 1, 1)); // array(1, 1, 1, 1)

$val = max(array(2, 4, 8), array(2, 5, 7)); // array(2, 5, 7)

$val = max('string', array(2, 5, 7), 42);   // array(2, 5, 7)?>

min()

If the first and only parameter is an

array, min() returns the lowest value in that

array. If at least two parameters are

provided, min() returns the smallest of these

values.

min() returns the numerically lowest of the

parameter values.

 min ( array $values )

 min (  $value1 ,  $value2 [,  $... ] )

min()

?php

echo min(2, 3, 1, 6, 7);  // 1

echo min(array(2, 4, 5)); // 2

echo min(0, 'hello');     // 0

echo min('hello', 0);     // hello

echo min('hello', -1);    // -1

?>

str_pad ()

This functions returns the input string padded on the left,

the right, or both sides to the specified padding length. If

the optional argument pad_string is not supplied,

the input is padded with spaces, otherwise it is padded

with characters from pad_string up to the limit.

Returns the padded string.

string str_pad ( string $input , int $pad_length [, string $pad_string = " " [, int $pad_type =

STR_PAD_RIGHT ]] )

str_pad ()<?php

$input = "Alien";

echo str_pad($input, 10);                      // produces "Alien     

"

echo str_pad($input, 10, "-

=", STR_PAD_LEFT);  // produces "-=-=-Alien"

echo str_pad($input, 10, "_", STR_PAD_BOTH);   // produces 

"__Alien___"

echo str_pad($input, 6 , "___");               // produces "Alien_“

?>

str_repeat ()

Returns input repeated multiplier times.

<?php

echo str_repeat("-=", 10);

?>

string str_repeat ( string $input , int $multiplier )

Array Functions

array_push() 

array_push () Push one or more elements

onto the end of array

Returns the new number of elements in

the array.

int array_push ( array &$array , $var [, mixed $... ] )

array_push() 

<?php

$stack = array("orange", "banana");

array_push($stack, "apple", "raspberry");

print_r($stack);

?>

array_push() 

array_pop — Pop the element off the end of array

Returns the last value of array. If array is empty (or is not

an array), NULL will be returned.

 array_pop ( array &$array )

array_pop() 

<?php

$stack = array("orange", "banana", "apple", "raspberry");

$fruit = array_pop($stack);

print_r($stack);

?>

array_merge() 

array_merge — Merge one or more arrays

Merges the elements of one or more arrays together so that the values of one are appended to the end of the previous one. It

returns the resulting array.

If the input arrays have the same string keys, then the later value for that key will overwrite the previous one. If, however, the

arrays contain numeric keys, the later value will not overwrite the original value, but will be appended.

Values in the input array with numeric keys will be renumbered with incrementing keys starting from zero in the result array.

Returns the resulting array.

array array_merge ( array $array1 [, array $... ] )

array_merge() 

<?php

$array1 = array("color" => "red", 2, 4);

$array2 = array("a", "b", "color" => "green", 4);

$result = array_merge($array1, $array2);

print_r($result);

?>

array_rand () 

array_rand — Pick one or more random entries out of an array

Picks one or more random entries out of an array, and returns the key (or keys) of the

random entries.

If you are picking only one entry, array_rand() returns the key for a random entry. Otherwise,

it returns an array of keys for the random entries. This is done so that you can pick random

keys as well as values out of the array.

 array_rand ( array $input [, int $num_req = 1 ] )

array_rand () 

<?php

$bmw = array(“X2", “X3", “X4", “X5", “X6");

$rand_keys = array_rand($bmw, 2);

echo $bmw[$rand_keys[0]] . "\n";

echo $bmw[$rand_keys[1]] . "\n";

?

array_replace () 

array_replace — Replaces elements from passed arrays into the first array

array_replace() replaces the values of the first array with the same values from all the following arrays. If a key from

the first array exists in the second array, its value will be replaced by the value from the second array. If the key exists in

the second array, and not the first, it will be created in the first array. If a key only exists in the first array, it will be left as

is. If several arrays are passed for replacement, they will be processed in order, the later arrays overwriting the previous

values.

array_replace() is not recursive : it will replace values in the first array by whatever type is in the second array.

Returns an array, or NULL if an error occurs.

array array_replace ( array $array , array $array1 [, array $... ] )

array_replace () 

<?php

$base = array("orange", "banana", "apple", "raspberry");

$replacements = array(0 => "pineapple", 4 => "cherry");

$replacements2 = array(0 => "grape");

$basket = array_replace($base, $replacements, $replacements2);

print_r($basket);

?>

range  () 

range — Create an array containing a range of

elements

Returns an array of elements from start to limit,

inclusive.

array range ( mixed $start , mixed $limit [, number $step = 1 ] )

range  () 

<?php

$numbers = range(0, 12) ;// array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)

foreach ($numbers  as $num) {     echo $num; }

// The step parameter was introduced in 5.0.0

$numbers = range(0, 100, 10) ;// array(0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100)

foreach ( $numbers as $num) {echo $num; }

// Use of character sequences introduced in 4.1.0

$letters = range('a', 'i'); // array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i');

foreach ($letters  as $let) {     echo $let; }

$letters = range('c', 'a') // array('c', 'b', 'a');

foreach ($letters  as $let) {     echo $let; }

?>

shuffle () 

This function shuffles (randomizes the order of

the elements in) an array.

Returns TRUE on success or FALSE on failure.

bool shuffle ( array &$array )

shuffle () 

<?php

$numbers = range(1, 20);

shuffle($numbers);

foreach ($numbers as $number) {

    echo "$number ";

}

?>

asort  () 

asort — Sort an array and maintain index

association

This function sorts an array such that array

indices maintain their correlation with the array

elements they are associated with. This is used

mainly when sorting associative arrays where the

actual element order is significant.

Returns TRUE on success or FALSE on failure.

bool asort ( array &$array [, int $sort_flags = SORT_REGULAR ] )

asort  () 

<?php

$fruits = array("d" => "lemon", "a" => "orange", "b" => "b

anana", "c" => "apple");

asort($fruits);

foreach ($fruits as $key => $val) {

    echo "$key = $val\n";

}

?>

usort  () 

usort — Sort an array by values using a user-defined

comparison function

This function will sort an array by its values using a user-

supplied comparison function. If the array you wish to sort

needs to be sorted by some non-trivial criteria, you should

use this function.

Returns TRUE on success or FALSE on failure.

bool usort ( array &$array , callable $cmp_function )

usort  () <?php

function cmp($a, $b)

{

    if ($a == $b) {

        return 0;

    }

    return ($a < $b) ? -1 : 1;

}

$a = array(3, 2, 5, 6, 1);

usort($a, "cmp");

foreach ($a as $key => $value) {

    echo "$key: $value\n";

}

?>

ksort  () 

Sorts an array by key, maintaining key to data

correlations. This is useful mainly for associative

arrays.

Returns TRUE on success or FALSE on failure.

bool ksort ( array &$array [, int $sort_flags = SORT_REGULAR ] )

ksort  () 

<?php

$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c

"=>"apple");

ksort($fruits);

foreach ($fruits as $key => $val) {

    echo "$key = $val\n";

}

?>

array_fill   () 

Fills an array with num entries of the

value of the value parameter, keys

starting at

the start_index parameter.

Returns the filled array.

array array_fill ( int $start_index , int $num , mixed $value )

array_fill() 

<?php

$a = array_fill(5, 6, 'banana');

$b = array_fill(-2, 4, 'pear');

print_r($a);

print_r($b);

?>