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  • PHP string to uppercase
    PHP string to uppercase
    There are four main ways to convert strings to uppercase in PHP, and the specific choice depends on the usage scenario. 1. Use strtoupper() to convert lowercase letters of the entire string to uppercase, which are suitable for English content, but do not support non-English characters with accents; 2. When dealing with multilinguals, mb_strtoupper() is recommended. It belongs to the mbstring extension and can correctly convert special characters such as French and German. It is recommended to specify the character set to UTF-8 when using it; 3. If you only need to convert the first letter, you can use ucfirst() to convert the first character of the string to uppercase; 4. If you want the first letter of each word to uppercase, you can use ucwords() to be used, which is suitable for formatting titles or usernames to display, but it does not recognize underscores by default.
    PHP Tutorial . Backend Development 944 2025-07-12 00:27:20
  • PHP header location vs javascript redirect
    PHP header location vs javascript redirect
    The jump mechanism of PHP ("Location:...") and JavaScript are different from the applicable scenarios. 1. The execution time is different: PHP is a server-side jump, and the browser jumps immediately after receiving the response, and does not depend on whether JS is enabled; JS is a browser-side jump, and the page is executed after the page is loaded, and it will be invalid if JS is disabled. 2. SEO friendly: PHP is more suitable for SEO, supports 301/302 status code, which is conducive to search engine recognition; JS is not friendly enough to crawlers. 3. Interactiveness: JS is more flexible and suitable for jumping based on user behavior or conditions. 4. Security and limitations: PHP uses header()
    PHP Tutorial . Backend Development 826 2025-07-12 00:23:11
  • PHP hide undefined index notice
    PHP hide undefined index notice
    When encountering the "undefinedindex" problem, you should give priority to using isset() to determine whether the index exists. 1. Using isset() can effectively avoid notice and apply to all arrays; 2. Array_key_exists() can distinguish whether the index exists and whether the value is null; 3. The empty merge operator?? (PHP7) can set the default value concisely and safely; 4. Resist error information is feasible but not conducive to maintenance. It is recommended to select isset(), array_key_exists() or ?? operators according to the scene to improve the robustness of the code.
    PHP Tutorial . Backend Development 754 2025-07-12 00:20:01
  • PHP function return type declarations
    PHP function return type declarations
    PHP function return type declarations can improve code clarity and robustness, especially for large projects and multi-person collaboration. By directly adding colons and types (such as :int and :string) after the function definition, the function can be forced to return data of the specified type. If the return value type does not match, an error will be thrown during runtime. Supported types include basic types, arrays, objects, callable objects and union types starting from PHP8 (such as: int|float). For cases where null may be returned, a ? prefix is ??available, such as:?string. The return type declaration itself does not need to enable strict_types to take effect, but it is recommended to enable strict mode in a unified way to maintain the consistent code style. Best practices include trying to identify the return type,
    PHP Tutorial . Backend Development 290 2025-07-12 00:04:41
  • How to URL encode a string in PHP with urlencode
    How to URL encode a string in PHP with urlencode
    The urlencode() function is used to encode strings into URL-safe formats, where non-alphanumeric characters (except -, _, and .) are replaced with a percent sign followed by a two-digit hexadecimal number. For example, spaces are converted to signs, exclamation marks are converted to!, and Chinese characters are converted to their UTF-8 encoding form. When using, only the parameter values ??should be encoded, not the entire URL, to avoid damaging the URL structure. For other parts of the URL, such as path segments, the rawurlencode() function should be used, which converts the space to . When processing array parameters, you can use http_build_query() to automatically encode, or manually call urlencode() on each value to ensure safe transfer of data. just
    PHP Tutorial . Backend Development 432 2025-07-11 03:22:01
  • How to compare two strings for similarity in PHP with similar_text or levenshtein
    How to compare two strings for similarity in PHP with similar_text or levenshtein
    In PHP, we mainly use similar_text() and levenshtein() functions to compare string similarity; 1. Similar_text() returns the similarity percentage or the number of matching characters, suitable for fuzzy search and repeated content detection; 2. levenshtein() returns the editing distance, suitable for automatic error correction and input correction; 3. The selection basis is the requirement: if the percentage is required, select similar_text(), and if the number of steps is required, use levenshtein().
    PHP Tutorial . Backend Development 986 2025-07-11 03:20:51
  • PHP get the last N characters of a string
    PHP get the last N characters of a string
    There are two main ways to get the last N characters of a string in PHP: 1. Use the substr() function to intercept through the negative starting position, which is suitable for single-byte characters; 2. Use the mb_substr() function to support multilingual and UTF-8 encoding to avoid truncating non-English characters; 3. Optionally determine whether the string length is sufficient to handle boundary situations; 4. It is not recommended to use strrev() substr() combination method because it is not safe and inefficient for multi-byte characters.
    PHP Tutorial . Backend Development 163 2025-07-11 03:17:20
  • PHP get the first N characters of a string
    PHP get the first N characters of a string
    You can use substr() or mb_substr() to get the first N characters in PHP. The specific steps are as follows: 1. Use substr($string,0,N) to intercept the first N characters, which is suitable for ASCII characters and is simple and efficient; 2. When processing multi-byte characters (such as Chinese), mb_substr($string,0,N,'UTF-8'), and ensure that mbstring extension is enabled; 3. If the string contains HTML or whitespace characters, you should first use strip_tags() to remove the tags and trim() to clean the spaces, and then intercept them to ensure the results are clean.
    PHP Tutorial . Backend Development 288 2025-07-11 03:17:00
  • How to prevent session hijacking in PHP?
    How to prevent session hijacking in PHP?
    To prevent session hijacking in PHP, the following measures need to be taken: 1. Use HTTPS to encrypt the transmission and set session.cookie_secure=1 in php.ini; 2. Set the security cookie attributes, including httponly, secure and samesite; 3. Call session_regenerate_id(true) when the user logs in or permissions change to change to change the SessionID; 4. Limit the Session life cycle, reasonably configure gc_maxlifetime and record the user's activity time; 5. Prohibit exposing the SessionID to the URL, and set session.use_only
    PHP Tutorial . Backend Development 226 2025-07-11 03:15:51
  • PHP explode string by delimiter
    PHP explode string by delimiter
    In PHP, use the exploit() function to split strings by separator. The basic usage is exploit(separator, string, limit), where separator is the required separator, string is the string to be split, and limit is the optional parameter to limit the number of array elements. For example, $arr=explode(",","apple,banana,orange") will return ['apple','banana','orange']; continuous separators such as "a,,b" will produce empty string elements; if the separator is an empty word
    PHP Tutorial . Backend Development 661 2025-07-11 03:15:21
  • How Do Generators Work in PHP?
    How Do Generators Work in PHP?
    AgeneratorinPHPisamemory-efficientwaytoiterateoverlargedatasetsbyyieldingvaluesoneatatimeinsteadofreturningthemallatonce.1.Generatorsusetheyieldkeywordtoproducevaluesondemand,reducingmemoryusage.2.Theyareusefulforhandlingbigloops,readinglargefiles,or
    PHP Tutorial . Backend Development 602 2025-07-11 03:12:10
  • How do you handle exceptions in php using `try...catch` blocks?
    How do you handle exceptions in php using `try...catch` blocks?
    Using try...catch blocks in PHP is an effective way to manage errors and unexpected behavior. 1. An exception is an object thrown during execution, indicating that a problem occurs, such as calling a non-objective method or opening a non-existent file. 2. The try block contains code that may have errors, the catch block catches and handles exceptions, and obtains messages, codes and other information through $e. 3. Multiple catch blocks can be used to handle different types of exceptions in a specific to common order. 4. Exceptions can be thrown manually to verify input or execute business rules, but abuse should be avoided. 5. It is recommended to use meaningful exception messages, create custom exception classes appropriately, and note that finally blocks can be used for cleaning operations.
    PHP Tutorial . Backend Development 407 2025-07-11 03:09:41
  • What is PHP Dependency Injection and its benefits?
    What is PHP Dependency Injection and its benefits?
    DependencyinjectioninPHPisadesignpatternthatenhancesflexibilityandtestabilitybyallowingdependenciestobepassedintoclassesratherthanhardcoded.Insteadofcreatingdependenciesinsideaclass,suchas$this->db=newDatabase();,dependencyinjectionpassesthemviaco
    PHP Tutorial . Backend Development 688 2025-07-11 03:02:41
  • How to use substr_replace in PHP
    How to use substr_replace in PHP
    substr_replace is a function in PHP to replace the contents of the specified position in a string. Its syntax is substr_replace($string,$replace,$start,$length), where $start represents the start position and $length is an optional parameter that represents the replacement length. For example, substr_replace("Helloworld!","PHP", 6, 5) output HelloPHP! Common uses include: 1. Replace the content of the specified location, such as replacing "sunny" with "rainy&quo
    PHP Tutorial . Backend Development 879 2025-07-11 03:00:40

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