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

To determine whether a parameter is in a PHP array, you can use the in_array() function. The syntax of this function is as follows:

bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

This function accepts three parameters:

• needle: The value to be found
• haystack: Array to find
• strict: Optional parameter, if set to true, the type will be considered when comparing values ​​

if specified Returns true if the $needle value is found in the $haystack array, otherwise returns false.

The following is an example:

$fruits = array("apple", "banana", "orange", "pear");
if (in_array("apple", $fruits)) {
  echo "苹果在水果篮子里";
} else {
  echo "苹果没有在水果篮子里";
}

The above code output:

苹果在水果篮子里

If the value to be checked is a number, strict mode must be used. The following is an example:

$numbers = array(1, 3, 5, 7);
if (in_array("3", $numbers, true)) {
  echo "3在数字数组里（使用严格模式）";
} else {
  echo "3没有在数字数组里（使用严格模式）";
}

The above code output:

3没有在数字数组里（使用严格模式）

If the value to be checked is a string, you can do it without using strict mode. The following is an example:

$alphabets = array("a", "b", "c", "d");
if (in_array("A", $alphabets)) {
  echo "A在字母数组里（不使用严格模式）";
} else {
  echo "A没有在字母数组里（不使用严格模式）";
}

The above code output:

A没有在字母数组里（不使用严格模式）

In short, to determine whether a parameter is in an array in PHP, you can use the in_array() function. This function is simple and ensures that the types of values ​​match by setting a strict mode.

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