How to remove the last three digits from a string in php

PHP language is one of the most common languages ​​​​for website development, and it is also a language that many programmers and developers like to use. In PHP, it is often necessary to process strings. For example, when processing numeric strings, removing the last three digits is a very common requirement.

Below we will introduce how to remove the last three digits from a string in PHP.

Method 1: Use the substr() function
The substr() function can intercept part of a string. Therefore, we can use it to remove the last three digits of a string.

The sample code is as follows:

$str = "123456789";
$new_str = substr($str, 0, -3); //去除后三位数字
echo $new_str; //输出 123456

In this example, we first define a string $str, and then use the substr() function to intercept it into a substring except the last three characters. , and finally assign the new string to the $new_str variable. We verify the correctness of the code by printing the $new_str variable.

Method 2: Use regular expressions
Regular expressions can match different types of strings. Therefore, you can use regular expressions to remove the last three digits from a string.

The sample code is as follows:

$str = "123456789";
$new_str = preg_replace('/\d{3}$/', '', $str); //去除后三位数字
echo $new_str; //输出 123456

In this example, we use the preg_replace() function to match the last three digits of the string and replace them. The regular expression "/\d{3}$/" means matching the last three digits in the string. Finally, assign the replaced new string to the $new_str variable.

It should be noted that "\d" in the regular expression means to match any number, which is equivalent to "[0-9]".

Method 3: Use the intval() function
The intval() function in PHP can convert a string into an integer. If the end of the string is a number, you can use the intval() function to remove it.

The sample code is as follows:

$str = "123456789";
$new_str = intval($str/1000)*1000; //去除后三位数字
echo $new_str; //输出 123456000

In this example, we first convert the string $str to an integer, then divide it by 1000, then multiply by 1000, and finally convert the result Assign value to $new_str variable. This will remove the last three digits from the string.

It should be noted that this method is usually more suitable for converting strings into integers and performing calculations.

Summary
When developing PHP applications, removing the last three digits from a string is a common requirement. We can use methods such as substr(), regular expressions, and intval() functions to achieve this function. Among them, the substr() function is the simplest and most direct, while regular expressions are more flexible and customizable. Which method to choose depends on actual business needs and personal preference.

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