How to intercept string array in php traversal

PHP is a scripting language for Web development and is widely used in the Web development industry. During PHP development, it is often necessary to traverse arrays to manipulate data. What should we do when we need to intercept a string array? Next we will introduce in detail how to intercept string arrays in PHP traversal.

1. What is a string array?

In PHP, a string array is a data structure containing multiple string elements. String array is a commonly used data type in PHP. It is defined as follows:

$array = array('str1', 'str2', 'str3', ...);

Among them, $array represents the string array, and str1, str2, str3, etc. represent each string element.

String arrays can access and operate each string element through loop traversal. Commonly used traversal methods include for loop, foreach loop, etc.

2. String array traversal

In PHP, string array traversal can be implemented using for loop, foreach loop and while loop.

1. for loop

The for loop is a common way to traverse an array, and traversal is implemented through a loop counter. The code is as follows:

$array = array('str1', 'str2', 'str3', 'str4', 'str5');
for($i = 0; $i < count($array); $i++){
    echo $array[$i].'<br>';
}

2. foreach loop

The foreach loop is a commonly used way to traverse an array in PHP, and is mainly used to traverse each element in the array. The code is as follows:

$array = array('str1', 'str2', 'str3', 'str4', 'str5');
foreach($array as $value){
    echo $value.'<br>';
}

3. while loop

The while loop is a common way to traverse an array, and a cursor is usually used to implement array traversal. The code is as follows:

$array = array('str1', 'str2', 'str3', 'str4', 'str5');
$i = 0;
while($i < count($array)){
    echo $array[$i].'<br>';
    $i++;
}

3. Intercepting a string array

In PHP, intercepting a string array can be implemented using the array_slice function, array_splice function and substr function.

1. array_slice function

Use the array_slice function to intercept a section of elements in the array. The syntax of this function is as follows:

array array_slice ( array $array , int $offset [, int $length = NULL [, bool $preserve_keys = false ]] )

Among them, $array represents the The intercepted array, $offset indicates the position of the interception starting point, $length indicates the length to be intercepted, $preserve_keys indicates whether to retain the original key name. If retained, the element key name of the new array will be the same as the original array.

The code is as follows:

$array = array('str1', 'str2', 'str3', 'str4', 'str5');
$new_array = array_slice($array, 1, 3);
print_r($new_array);

The output result is as follows:

Array (
    [0] => str2
    [1] => str3
    [2] => str4
)

2. array_splice function

Use the array_splice function to intercept a segment of the array element, delete the element in the original array, and insert other new elements. The syntax of this function is as follows:

array array_splice ( array &$array , int $offset [, int $length = NULL [, mixed $replacement = array() ]] )

Among them, $array represents the array to be intercepted, $offset represents the position of the starting point of interception, $length represents the length to be intercepted, and $replacement is the new element inserted into the array. If not specified, the element in the original array will be deleted.

The code is as follows:

$array = array('str1', 'str2', 'str3', 'str4', 'str5');
$new_array = array_splice($array, 1, 3);
print_r($new_array);

The output result is as follows:

Array (
    [0] => str2
    [1] => str3
    [2] => str4
)

3. substr function

Use the substr function to intercept part of the string , the syntax of this function is as follows:

string substr ( string $string , int $start [, int $length ] )

Among them, $string represents the string to be intercepted, $start represents the starting point of interception, and $length represents the length to be intercepted.

The code is as follows:

$array = array('str1', 'str2', 'str3', 'str4', 'str5');
foreach($array as $value){
    echo substr($value, 0, 2).'<br>';
}

The output result is as follows:

st
st
st
st
st

4. Summary

In the PHP development process, it is often necessary to use array traversal to Operation data. When we need to intercept a string array, we can use the array_slice function, array_splice function and substr function to achieve this. We can choose the appropriate function to intercept the string array according to actual needs.

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