There are many string functions in php. For example, you need to filter the spaces at the end of the string first, and then find its length. The general way of writing is:
strlen(trim($str))
If you want to implement a chain operation similar to that in js , for example, how should I write like the following?
$str->trim()->strlen()
The following are implemented in three ways:
Method 1. Use magic function __call combined with call_user_func to achieve
Idea: First define A string class StringHelper, the constructor directly assigns value, and then calls the trim() and strlen() functions in a chain. The calling relationship is handled by using call_user_func in the called magic function __call(). The implementation is as follows:
<?php class StringHelper { private $value; function __construct($value) { $this->value = $value; } function __call($function, $args){ $this->value = call_user_func($function, $this->value, $args[0]); return $this; } function strlen() { return strlen($this->value); } } $str = new StringHelper(" sd f 0"); echo $str->trim('0')->strlen();
Terminal execution script:
php test.php 8
Method 2. Use magic function __call combined with call_user_func_array to implement
<?php class StringHelper { private $value; function __construct($value) { $this->value = $value; } function __call($function, $args){ array_unshift($args, $this->value); $this->value = call_user_func_array($function, $args); return $this; } function strlen() { return strlen($this->value); } } $str = new StringHelper(" sd f 0"); echo $str->trim('0')->strlen();
Instructions:
array_unshift(array,value1,value2,value3...)
array_unshift( ) function is used to insert new elements into an array. The values of the new array will be inserted at the beginning of the array.
call_user_func() and call_user_func_array are both methods of dynamically calling functions. The difference lies in the way parameters are passed.
Method three, do not use the magic function __call to achieve
Just modify _call() to trim() function:
public function trim($t) { $this->value = trim($this->value, $t); return $this; }
The key point is to return the $this pointer to facilitate calling the latter function.
Recommended: "PHP Video Tutorial"
The above is the detailed content of Three ways to implement chain operations in PHP. For more information, please follow other related articles on the PHP Chinese website!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Zend Studio 13.0.1
Powerful PHP integrated development environment

Atom editor mac version download
The most popular open source editor

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Dreamweaver Mac version
Visual web development tools
