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Strings and Arrays. String. Is a sequence of characters. Example: “hello” , “how are you?” , “123”,and “!@#$%” are all valid string values. Creating and Accessing a String. $myString = ‘hello‘; $myString = “hello”; <?php $myString='hello there!'; echo "Hello $myString";

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string
String

Is a sequence of characters.

Example: “hello” , “how are you?” , “123”,and “!@#$%” are all valid string values.

creating and accessing a string
Creating and Accessing a String

$myString = ‘hello‘;

$myString = “hello”;

<?php $myString='hello there!';

echo "Hello $myString";

echo 'Hello $myString';

?>

slide4
{ }

use the curly brackets to distinguish the variable name from the rest of the string

$myFavorite=”cat”;

echo “My favorite animals are {$myFavorite}s”;

accessing characters within a string
Accessing Characters within a String

$myString=”hello world”;

echo $myString[0]; // displays h

slide6

String Functions

  • strlen() - Calculating length of array

<?php

$name = “Simon Stobart”;

$stringlength = strlen($name);

echo $stringlength;

?>

string functions
String Functions

str_word_count() - returns the number of words in a string

echo str_word_count(“Hello There”); // returns 2

string functions1
String Functions

Substr() - extract sequence of characters in a string

The string to extract the characters from

The position to start extracting the characters. If you use a negative number, substr() counts backward from the end of the string

The number of characters to extract. If you use a negative number, substr() misses that many characters from the end of the string instead. This parameter is optional; if left out, substr()extracts from the start position tothe end of the string

slide9
$myString = “Hello, world!”;

echo substr( $myString, 0, 5 ) . “ < br/ > ”; // Displays ‘Hello’

echo substr( $myString, 7 ) . “ < br/ > ”; // Displays ‘world!’

echo substr( $myString, -1 ) . “ < br/ > ”; // Displays ‘!’

echo substr( $myString, -5, -1 ) . “ < br/ > ”; // Displays ‘orld’

string functions2
String Functions

strpos() - find out exactly where a string of text occurs within another string

$myString = “Hello, world!”;

echo strpos( $myString, “wor” ); // Displays ‘7’

echo strpos( $myString, “xyz” ); // Displays ‘’ (false)

slide11
strrpos() - finds the last match in the string, rather than the first

$myString = “Hello, world!”;

echo strpos( $myString, “o” ) . “ < br / > ”; // Displays ‘4’

echo strrpos( $myString, “o” ) . “ < br / > ”; // Displays ‘8’

string functions3
String Functions

substr_count() - returns the number of times the text was found in the string

$myString = “I say, nay, nay, and thrice nay!”;

echo substr_count( $myString, “nay” ); // Displays ‘3’

string functions4
String Functions

strpbrk() - returns the

portion of the string from the first matched character to the end of the string. If none of the characters in

the set are found in the string, strpbrk() returns false .

slide14
$myString = “Hello, world!”;

echo strpbrk( $myString, “abcdef” ); // Displays ‘ello, world!’

echo strpbrk( $myString, “xyz” ); // Displays ‘’ (false)

$username = “matt@example.com”;

if ( strpbrk( $username, “@!” ) ) echo “@ and ! are not allowed in usernames”;

slide15

String Functions

  • strstr(searchstring, lookingstring)
    • find a specific part of a string inside another string, returns the remainder of the input string

<?php

$name = “Simon Stowart”;

$strOutput =strstr($name,”St”);

echo “The result is”.$strOutput;

?>

slide16

String Functions

  • str_replace(lookingforstring,replatestring,searchstring)
    • Replace parts of the string with another string
slide17

<?php

$strSentence="The use of italics can be useful to highlight certain words. ";

$strOutput = str_replace("italics","<i>italics</i>",$strSentence);

echo $strSentence ."<br>";

echo "The output now looks like: ".$strOutput;?>

?>

string functions5
String Functions

substr_replace() replaces a specified portion of the target string with another string

$myString = “It was the best of times, it was the worst of times,”;

// Displays “It was the bananas”

echo substr_replace( $myString, “bananas”, 11 ) . “ < br/ > ”;

slide19

String Functions

  • strrev(string)
    • Returns the string in reverse order

<?php

$name = “Simon Stowart”;

$strOutput = strrev($name);

echo $name. “backwards is ”.$strOutput;

?>

slide20

String Functions

  • strtoupper(), strtolower(),ucfirst(),ucwords();
    • Changes the case of string
slide21

<?php

echo strtoupper("simon stowart")."<br>".strtolower("SIMON SOTWART");

echo "<br>".ucfirst("simon stowart")."<br>".ucwords("simon stowart");?>

?>

formatting functions
Formatting Functions

printf()

trim() removes white space from the beginning and end of a string

ltrim() removes white space only from the beginning of a string

rtrim() removes white space only from the end of a string

slide23

Array

  • Syntax
    • theArray = array(array1,array2… ,arrayN);
    • $arrColors = array(“Red”,”Blue”,”Yellow”,”White”);
slide24

<?php

$arrColors = array(“Red”,”Blue”,”Yellow”,”White”);

for ($ctr = 0; $ctr < 5; $ctr++)

echo “<p>”.$arrColors[$ctr].”<p>”;

?>

slide25

Array

  • Accessing array elements
    • Index or key
slide26

<?php

$arrColors = array(0=>"Red",1=>"Blue",3=>"Yellow",5=>"White");

for ($ctr = 0; $ctr < 6; $ctr++)

echo "<p>".$arrColors[$ctr]."<p>";

?>

slide27

foreach(array as value) statement

<?php

$arrColors = array(0=>"Red",1=>"Blue",3=>"Yellow",5=>"White");

$ctr =0;

foreach ($arrColors as $strColor)

{

echo "<p>".$ctr ." " .$strColor."<p>";

$ctr++;

}

?>

slide28

Arrays

  • Nonmerical keys

<?php

$arrColors = array("red"=>"Red","blue"=>"Blue","yello"=>"Yellow","white"=>"White");

foreach ($arrColors as $strkey => $strColor)

echo "<p>".$strkey ." : " .$strColor."<p>";

?>

slide29

Multi-dimensional array

<?php

$arrCars = array (array("Fords","Mazda","Toyota"),

array("Blue","Red","Green"),

array(1,2,4));

for ($ctr = 0; $ctr <3; $ctr++){

$makar = $arrCars[0][$ctr];

$color = $arrCars[1][$ctr];

$qty = $arrCars[2][$ctr];

echo "<p> Maka: ".$maker." Color: ".$color. " Quantity: ".$qty ."</p>";

}

?>

slide30

Counting array elements

$size = count(array)

slide31

Creating Stack

  • array_pop(array)
  • array_push(array,element)
slide32

Example

<?php

$arrColor = array("Red","Blue");

print_r($arrColor);

$strColor = array_pop($arrColor);

echo "<br> Deleted color: ".$strColor."<br>";

print_r($arrColor);

array_push($arrColor,"Green");

echo "<br>";

print_r($arrColor);

?>

slide33

Explode

  • Array = explode(separator, string);
  • the first string indicating the what characters will be use to search the string to separate it into individual array elements
  • The second parameter is the string itself
slide34

<?php

$pizza = "piece1 piece2 piece3 piece4 piece5 piece6";

$pieces = explode(" ", $pizza);

print_r($pieces);

?>

slide35

Implode

  • String = implode(separator, array);
  • The first string indicating what characters it will use to separate each element and the second is an array
slide36

<?php

$array = array('lastname', 'email', 'phone');

$comma_separated = implode(",", $array);

echo $comma_separated; // lastname,email,phone

?>

slide37

Using arrays in forms

<?php

$arrNames = array("Simon","Liz","Gemma","Hayley");

$strNames = implode("|",$arrNames);

?>

<html>

<body>

<form method = "post" action="display.php">

<input type = "hidden" name="strNames" value =" <?php echo $strNames; ?>">

<br>

<br>

<input type = "text" name="names" maxlength="50" >

<input type = "submit" name="submit" value="click">

</form>

</body>

</html>

slide38

<?php

if(isset($_POST['submit'])){

echo "<p> The array contains: </p>";

$strNames = $_POST['strNames']."|".$_POST['names'];

$arrNames = explode("|",$strNames);

foreach($arrNames as $key => $value)

echo "<p>[". $key ."]".$value ."</p>";

}

?>