76少妇精品导航,xxxx18野外xxxxfreexxxx日本,av人摸人人人澡人人超碰手机版

Home

Backend Development

PHP Tutorial

String comparison using == operator in PHP_PHP Tutorial

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jul 21, 2016 pm 03:59 PM

php superior publish string most Compare use of operator conduct

A new article comparing strings in PHP with the == operator recently published on Greg Beaver's blog mentioned issues worth noting when comparing strings with PHP's == operator.

In some cases, PHP will convert numerical data (such as strings containing numbers, etc.) into numerical processing, and the == operator is one of them. When using the == operator to loosely compare two strings, PHP will convert -like numerical strings into numerical values ??for comparison. The following experiment confirms this conclusion:
<code> <?php var_dump('01' == 1); ?> var_dump('01' == 1);
?>

The output result of the above code is:
bool(true) Therefore, when using When comparing strings, it is recommended to use the === operator to strictly check the strings, or use functions such as strcmp() to avoid possible problems. The "PHP Type Comparison Table" in the PHP manual also explains this in detail.

<?php var_dump(in_array('01', array('1'))); ?> In addition, the commonly used in_array() function also has weak type problems, see the following code:

<?php var_dump(in_array('01' , array('1'))); ?>Above The code output result is: bool(true)

I believe that PHP programmers who have used this function for security checks know what kind of security problems this will cause, right? Fortunately, the <?php var_dump(in_array('01', array('1'), true)); ?> in_array() function provides us with a third parameter. Setting it to true can turn on the mandatory type checking mechanism of the
in_array() function, as shown in the following code:

&lt ;?php var_dump(in_array('01', array('1'), true)); ?>

truehttp: //www.bkjia.com/PHPjc/317213.htmlTechArticle mentioned in a new article recently published on Greg Beaver's blog comparing strings in PHP with the == operator As for the issues worth noting when comparing strings with PHP's == operator...

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress images for free

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

AI clothes remover

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Guide: Stellar Blade Save File Location/Save File Lost/Not Saving

4 weeks ago By DDD

Oguri Cap Build Guide | A Pretty Derby Musume

2 weeks ago By Jack chen

Agnes Tachyon Build Guide | A Pretty Derby Musume

1 weeks ago By Jack chen

Dune: Awakening - Advanced Planetologist Quest Walkthrough

4 weeks ago By Jack chen

Date Everything: Dirk And Harper Relationship Guide

4 weeks ago By Jack chen

Hot Tools

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Where is the login entrance for gmail email?

8637

Java Tutorial

1783

CakePHP Tutorial

1728

Laravel Tutorial

1577

PHP Tutorial

1442

Related knowledge

How to get the current session ID in PHP? Jul 13, 2025 am 03:02 AM

The method to get the current session ID in PHP is to use the session_id() function, but you must call session_start() to successfully obtain it. 1. Call session_start() to start the session; 2. Use session_id() to read the session ID and output a string similar to abc123def456ghi789; 3. If the return is empty, check whether session_start() is missing, whether the user accesses for the first time, or whether the session is destroyed; 4. The session ID can be used for logging, security verification and cross-request communication, but security needs to be paid attention to. Make sure that the session is correctly enabled and the ID can be obtained successfully.

PHP get substring from a string Jul 13, 2025 am 02:59 AM

To extract substrings from PHP strings, you can use the substr() function, which is syntax substr(string$string,int$start,?int$length=null), and if the length is not specified, it will be intercepted to the end; when processing multi-byte characters such as Chinese, you should use the mb_substr() function to avoid garbled code; if you need to intercept the string according to a specific separator, you can use exploit() or combine strpos() and substr() to implement it, such as extracting file name extensions or domain names.

How do you perform unit testing for php code? Jul 13, 2025 am 02:54 AM

UnittestinginPHPinvolvesverifyingindividualcodeunitslikefunctionsormethodstocatchbugsearlyandensurereliablerefactoring.1)SetupPHPUnitviaComposer,createatestdirectory,andconfigureautoloadandphpunit.xml.2)Writetestcasesfollowingthearrange-act-assertpat

How to split a string into an array in PHP Jul 13, 2025 am 02:59 AM

In PHP, the most common method is to split the string into an array using the exploit() function. This function divides the string into multiple parts through the specified delimiter and returns an array. The syntax is exploit(separator, string, limit), where separator is the separator, string is the original string, and limit is an optional parameter to control the maximum number of segments. For example $str="apple,banana,orange";$arr=explode(",",$str); The result is ["apple","bana

JavaScript Data Types: Primitive vs Reference Jul 13, 2025 am 02:43 AM

JavaScript data types are divided into primitive types and reference types. Primitive types include string, number, boolean, null, undefined, and symbol. The values are immutable and copies are copied when assigning values, so they do not affect each other; reference types such as objects, arrays and functions store memory addresses, and variables pointing to the same object will affect each other. Typeof and instanceof can be used to determine types, but pay attention to the historical issues of typeofnull. Understanding these two types of differences can help write more stable and reliable code.

Using std::chrono in C Jul 15, 2025 am 01:30 AM

std::chrono is used in C to process time, including obtaining the current time, measuring execution time, operation time point and duration, and formatting analysis time. 1. Use std::chrono::system_clock::now() to obtain the current time, which can be converted into a readable string, but the system clock may not be monotonous; 2. Use std::chrono::steady_clock to measure the execution time to ensure monotony, and convert it into milliseconds, seconds and other units through duration_cast; 3. Time point (time_point) and duration (duration) can be interoperable, but attention should be paid to unit compatibility and clock epoch (epoch)

How to pass a session variable to another page in PHP? Jul 13, 2025 am 02:39 AM

In PHP, to pass a session variable to another page, the key is to start the session correctly and use the same $_SESSION key name. 1. Before using session variables for each page, it must be called session_start() and placed in the front of the script; 2. Set session variables such as $_SESSION['username']='JohnDoe' on the first page; 3. After calling session_start() on another page, access the variables through the same key name; 4. Make sure that session_start() is called on each page, avoid outputting content in advance, and check that the session storage path on the server is writable; 5. Use ses

How does PHP handle Environment Variables? Jul 14, 2025 am 03:01 AM

ToaccessenvironmentvariablesinPHP,usegetenv()orthe$_ENVsuperglobal.1.getenv('VAR_NAME')retrievesaspecificvariable.2.$_ENV['VAR_NAME']accessesvariablesifvariables_orderinphp.iniincludes"E".SetvariablesviaCLIwithVAR=valuephpscript.php,inApach

See all articles

国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂