How to determine whether an array exists in a string in php

With the development and progress of Internet technology, PHP, as a very popular scripting language, is widely used in Web development. In PHP development, the application of arrays is also very common. In actual development, we often encounter situations where we need to determine whether an array exists in a string. So, this article will specifically introduce how to determine whether an array exists in a string in PHP.

1. How to use the in_array function in PHP

In PHP, a common method to determine whether an array exists in another array is to use the in_array() function. The in_array() function is used to determine whether a value is in the array. It returns true if it exists and false if it does not exist. Its basic syntax structure is as follows:

in_array( value, array, bool )

Among them, value represents the value to be found, array represents the array to be found, and bool represents whether to use strict mode, that is Whether to consider type. The parameter bool defaults to false, which means that the type is ignored. If bool is set to true, the types of value and array must strictly match.

Then, we can use the in_array() function to determine whether an array exists in a string. The basic code is as follows:

$arr ​​= array("apple", "banana", " cherry");

$str = "I like apple pie.";

if (in_array($arr, $str)) {

echo "Match found.";

} else {

echo "Match not found.";

}

Among them, the $arr array represents the array to be searched for existence, and $str represents the string to be searched for. If any member of the array $arr is found in the string $str, then "Match found." is returned, otherwise "Match not found." is returned.

2. How to use the strpos() function in PHP

In addition to the in_array() function, there is also the strpos() string function in PHP that can be used to determine whether an array exists in a character String in. The strpos() function is used to search for a specified character or string in a string. Its basic syntax structure is as follows:

strpos(haystack, needle, offset)

Among them, haystack represents the string within which needle is found, needle represents the string to be found, and offset represents the start. Search location. If needle is not found, returns false; otherwise, returns the position of the character or substring in the haystack.

Then, we can use the strpos() function to determine whether an array exists in a string. The basic code is as follows:

$arr ​​= array("apple", "banana", " cherry");

$str = "I like apple pie.";

foreach ($arr as $fruit) {

if (strpos($str, $fruit) !== false) {

    echo "Match found.";

    break;

}

}

Among them, the $arr array represents the array to be searched, and $str represents the string to be searched for. Use a foreach loop to iterate through each member in the array $arr, use the strpos() function in the loop to find whether each member is in the string $str, if found, return "Match found." and end the loop, otherwise continue Loop until found.

3. Comparison of the two methods

Although both the in_array() function and strpos() function can be used to determine whether an array exists in a string, there are still some differences between them. the difference. We compare the differences between the two from the following aspects.

1. Usage and parameters are different

The parameters of the in_array() function include the value and array to be found, while the parameters of the strpos() function include the string and substring to be found. Specifically, the in_array() function is similar to the array function, while the strpos() function is a string function.

2. The case sensitivity of arrays and strings is different

The in_array() function is case-insensitive by default, while the strpos() function is case-sensitive. If you want to set case sensitivity in the in_array() function, you need to set its third parameter to true.

3. The situation of multiple matches is handled differently

If multiple matches are found in the string, the strpos() function only returns the position of the first match, while in_array () function can return multiple matches.

4. Conclusion

This article mainly introduces two methods in PHP to determine whether an array exists in a string: in_array() function and strpos() function. Although these two methods have their own advantages and limitations, they can be used flexibly in actual development and the appropriate method can be selected according to specific scenarios. No matter which method is used, as long as it can help developers implement functions efficiently, it is a good method.

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