Introduction to common PHP functions and their usage

PHP is a very versatile programming language that is widely used in the field of web development. In PHP, functions are an important tool that can help us complete various tasks. Therefore, it is very necessary to be proficient in common PHP functions and their usage. Below, I will introduce you to some common PHP functions and their usage.

1. strlen()

This function can return the length of a string, which is the number of characters it contains. The usage is as follows:

$len = strlen("Hello World");
echo $len; // 输出 11

2. strpos()

This function can search a string for another string and return the position of the string. If the string is not found, false is returned. The usage is as follows:

$str = "Hello World";
$pos = strpos($str, "World");
echo $pos; // 输出 6

3. explode()

This function can split a string into an array, and the delimiter can be any character. The usage is as follows:

$str = "apple,banana,orange";
$arr = explode(",", $str);
print_r($arr); // 输出 Array ( [0] => apple [1] => banana [2] => orange )

4. implode()

This function is the opposite of explode(). It can combine the elements of an array into a string and use the specified separator. The usage is as follows:

$arr = array("apple", "banana", "orange");
$str = implode(",", $arr);
echo $str; // 输出 apple,banana,orange

5. substr()

This function can return a substring of a string, the usage is as follows:

$str = "Hello World";
$sub = substr($str, 0, 5);
echo $sub; // 输出 Hello

6. str_replace ()

This function can replace certain characters in a string with other characters. The usage is as follows:

$str = "Hello World";
$new_str = str_replace("World", "PHP", $str);
echo $new_str; // 输出 Hello PHP

7. array_push()

This function can add one or more elements to the end of the array. The usage is as follows:

$arr = array("apple", "banana");
array_push($arr, "orange");
print_r($arr); // 输出 Array ( [0] => apple [1] => banana [2] => orange )

8. array_pop()

This function can delete the last element in the array and return the value of the element. The usage is as follows:

$arr = array("apple", "banana", "orange");
$last = array_pop($arr);
echo $last; // 输出 orange

9. array_shift()

This function can delete the first element in the array and return the value of the element. Usage is as follows:

$arr = array("apple", "banana", "orange");
$first = array_shift($arr);
echo $first; // 输出 apple

10. array_unshift()

This function can add one or more elements to the beginning of the array. The usage is as follows:

$arr = array("apple", "banana");
array_unshift($arr, "orange");
print_r($arr); // 输出 Array ( [0] => orange [1] => apple [2] => banana )

The above is an introduction to common PHP functions and their usage. Of course, there are many more functions in PHP, and the above are just a small part of them. In practical applications, we need to choose appropriate functions according to specific needs to complete the corresponding tasks.

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