- Listing of String Functions
- Using the String Functions
- Formatting Strings
- Converting to and from Strings
- Creating Arrays
- Modifying Arrays
- Removing Array Elements
- Looping Over Arrays
- Listing of the Array Functions
- Sorting Arrays
- Navigating through Arrays
- Imploding and Exploding Arrays
- Extracting Variables from Arrays
- Merging and Splitting Arrays
- Comparing Arrays
- Manipulating the Data in Arrays
- Creating Multidimensional Arrays
- Looping Over Multidimensional Arrays
- Using the Array Operators
- Summary
This chapter is from the book
This chapter is from the book
This chapter is from the book
Looping Over Arrays
You already know you can loop over an array using a for loop and the count function, which determines how many elements an array contains:
<?php
$fruits[0] = "pineapple";
$fruits[1] = "pomegranate";
$fruits[2] = "tangerine";
for ($index = 0; $index < count($fruits); $index++){
echo $fruits[$index], "\n";
}
?>
Here's what you get:
pineapple pomegranate tangerine
There's also a function for easily displaying the contents of an array, print_r:
<?php
$fruits[0] = "pineapple";
$fruits[1] = "pomegranate";
$fruits[2] = "tangerine";
print_r($fruits);
?>
Here are the results:
Array
(
[0] => pineapple
[1] => pomegranate
[2] => tangerine
)
The foreach statement was specially created to loop over collections such as arrays. This statement has two forms:
foreach (array_expression as $value) statement foreach (array_expression as $key => $value) statement
The first form of this statement assigns a new element from the array to $value each time through the loop. The second form places the current element's key, another name for its index, in $key and its value in $value each time through the loop. For example, here's how you can display all the elements in an array using foreach:
<?php
$fruits = array("pineapple", "pomegranate", "tangerine");
foreach ($fruits as $value) {
echo "Value: $value\n";
}
?>
Here are the results:
Value: pineapple Value: pomegranate Value: tangerine
And here's how you can display both the keys and values of an array:
<?php
$fruits = array("pineapple", "pomegranate", "tangerine");
foreach ($fruits as $key => $value) {
echo "Key: $key; Value: $value\n";
}
?>
Here are the results:
Key: 0; Value: pineapple Key: 1; Value: pomegranate Key: 2; Value: tangerine
You can even use a while loop to loop over an array if you use a new function, each . The each function is meant to be used in loops over collections such as arrays; each time through the array, it returns the current element's key and value and then moves to the next element. To handle a multiple-item return value from an array, you can use the list function, which will assign the two return values from each to separate variables.
Here's what this looks like for our $fruits array:
<?php
$fruits = array("pineapple", "pomegranate", "tangerine");
while (list($key, $value) = each ($fruits)) {
echo "Key: $key; Value: $value\n";
}
?>
Here's what you get from this script:
Key: 0; Value: pineapple Key: 1; Value: pomegranate Key: 2; Value: tangerine