How to determine whether a character is in an array in php

In PHP, there are many methods to determine whether a character is in an array.

1. Use the in_array() function

The in_array() function can be used to determine whether a value is in an array, and the return value is true or false.

Sample code:

$array = array('apple', 'banana', 'orange');
if (in_array('apple', $array)) {
    echo 'yes';
} else {
    echo 'no';
}

The output result is: yes

2. Use array_search() function

array_search() function can be used to find a value The position in the array, or false if it does not exist.

Sample code:

$array = array('apple', 'banana', 'orange');
$key = array_search('banana', $array);
if ($key !== false) {
    echo 'yes';
} else {
    echo 'no';
}

The output result is: yes

3. Use the in_array() function and strict parameters

The third of the in_array() function One parameter can specify whether case sensitivity is required. If case sensitivity is required, specify true.

Sample code:

$array = array('apple', 'banana', 'orange');
if (in_array('Apple', $array, true)) {
    echo 'yes';
} else {
    echo 'no';
}

The output result is: no

4. Use the array_search() function and strict parameters

The third of the array_search() function Each parameter can also specify whether it is case-sensitive.

Sample code:

$array = array('apple', 'banana', 'orange');
$key = array_search('Apple', $array, true);
if ($key !== false) {
    echo 'yes';
} else {
    echo 'no';
}

The output result is: no

5. Use the in_array() function and array_map() function

array_map() function Convert all values ​​in an array to lowercase or uppercase before making a judgment.

Sample code:

$array = array('apple', 'banana', 'orange');
$lower_array = array_map('strtolower', $array);
if (in_array('apple', $lower_array)) {
    echo 'yes';
} else {
    echo 'no';
}

The output result is: yes

6. Use array_search() function and array_map() function

Similarly, use array_map( ) function can convert all the values ​​in an array to lowercase or uppercase before searching.

Sample code:

$array = array('apple', 'banana', 'orange');
$lower_array = array_map('strtolower', $array);
$key = array_search('Apple', $lower_array);
if ($key !== false) {
    echo 'yes';
} else {
    echo 'no';
}

The output result is: yes

To sum up, you can use the in_array() function and array_search() function to determine whether a character is in the array. And the parameters of related functions are case-sensitive and other operations. In actual development, choosing the appropriate method according to the specific situation can improve code efficiency.

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