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- How to use php array_filter
- Common uses of array_filter include filtering empty values, filtering elements by condition, processing associative arrays, and preserving original key names. 1. Filter empty values: remove false values ??by default, such as null, empty string, 0 and false; 2. Filter by condition: If you select numbers greater than 10; 3. Process associative arrays: If you filter users older than 30; 4. Keep the original key name: If you need continuous index, you need to call array_values ??manually. Mastering these usages can improve data processing efficiency.
- PHP Tutorial . Backend Development 947 2025-07-02 15:10:03
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- How to convert php array to json string?
- In PHP, converting arrays to JSON strings mainly uses the json_encode function. 1. Use json_encode($array) to directly convert the array to standard JSON format; 2. If you need to format the output, you can add the JSON_PRETTY_PRINT parameter to achieve indentation and line breaks; 3. If you need to retain Chinese instead of escape to Unicode, you can use the JSON_UNESCAPED_UNICODE parameter; 4. Pay attention to distinguish the output differences between the index array and the associated array; 5. Make sure that the data does not contain resource types or circular references to avoid conversion errors; 6. You can check whether the conversion is successful through json_last_error(). The above method and
- PHP Tutorial . Backend Development 656 2025-07-02 15:09:00
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- How to use php date function?
- PHP's date() function is one of the most commonly used methods to deal with dates and times. It can format timestamps to the date and time format you want. It's not difficult to use, but some details are prone to errors. Basic usage: The most basic usage of formatting the current time date() is to output the current time. You only need to pass in a format string: echodate("Y-m-dH:i:s"); The above line of code will output a result like this: 2025-04-0514:30:45 Where: Y is a four-digit year (such as 2025), m is a two-digit month (01 to 12), d is a two-digit date (01 to 31), H is a 24-hour hour (00 to 2
- PHP Tutorial . Backend Development 539 2025-07-02 14:55:50
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- How to use php array_diff
- The array_diff function is used to compare array difference sets and returns elements unique to the first array. It compares and retains the original key name according to the value. For example, after comparing $array1 and $array2, only 1 and 2 in $array1; if the values ??are the same, they are still considered duplicates even if the keys are different; multiple arrays can be passed to find the difference set, such as only 1 is retained after comparing $array1, $array2 and $array3. Common uses include data deduplication, permission control and data synchronization. Pay attention to its characteristics of not comparing key names, and use array_values ??to re-index the results if necessary.
- PHP Tutorial . Backend Development 638 2025-07-02 14:47:11
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- How to define a php function
- The key to defining PHP functions is to master the basic structure and common usage. First, use the function keyword to define the function, the syntax is function function name (parameter list) { function body; return return value;}, for example function say Hello($name) {echo"Hello,$name!";}; secondly, the function name is not case sensitive, but it is recommended to be consistent, and it must be defined first and then called; then the parameters can be set default values, such as functiongreet($name="Guest") {echo"Welcome,$name";};
- PHP Tutorial . Backend Development 317 2025-07-02 14:40:02
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- How to get first element of php array?
- Getting the first element of an array in PHP can be achieved through a variety of methods. 1. Using the reset() function is the most direct method. It is suitable for indexing arrays and associative arrays, and resetting the array pointer to the first element; 2. If you need to obtain keys and values ??at the same time, you can use the key() and current() functions; 3. For associative arrays, you can also use array_values() to extract the value first and then obtain the first element through index [0]. This method is easy to understand and maintain. These methods flexibly respond to needs in different scenarios.
- PHP Tutorial . Backend Development 220 2025-07-02 14:39:01
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- How to document a php function?
- Writing PHP function annotations can improve code readability and collaboration efficiency. 1. Use the PHPDoc standard format, including function description, detailed description, @param, @return and @throws and other tags; 2. It must include function description, parameter description, return value and exception handling; 3. You can automatically generate annotation templates with the help of the IDE, use static analysis tools to check type matching, and output project documents through the document generator. Following these methods can quickly understand the purpose of functions and improve code maintenance.
- PHP Tutorial . Backend Development 548 2025-07-02 14:37:00
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- How to slice php array
- array_slice() is a method used in PHP to extract part of the array data. Its syntax is array_slice(array$array,int$offset,?int$length=null,bool$preserve_keys=false); the parameter $array is the original array, $offset is the starting index (supports negative numbers), and $length is the intercept length (can be omitted, default to the end), and $preserve_keys decide whether to retain the original key name (default reset to numeric index); for example, $fruits=['apple','banana','cherry','date'],
- PHP Tutorial . Backend Development 852 2025-07-02 14:35:32
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- How to use php die function?
- Common scenarios for using die() include checking the code execution process, viewing variable values, and quickly interrupting scripts. Common uses include outputting plain text, variable content or JSON data. Be careful to avoid abuse in production environments. They can be encapsulated into debugging tools to improve security and convenience.
- PHP Tutorial . Backend Development 177 2025-07-02 14:34:51
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- How to access php array element
- The key to accessing PHP array elements is to clarify the array type and use the correct syntax. 1. Use brackets[] to access directly: Use numeric indexes for indexing arrays (such as $array[0]), and use string key names and quotes for associative arrays (such as $array['key']); 2. Iterate over the array to access elements: univariate foreach traversal only gets the value, and bivariate foreach gets the keys and values ??at the same time; 3. Multidimensional array access requires multiple brackets to be used in order according to the level. Note that indexes start at 0, accessing non-existent keys or indexes may trigger warning or return null, while traversal is suitable for batch operations and processing elements one by one. Mastering these methods can flexibly read various array contents.
- PHP Tutorial . Backend Development 953 2025-07-02 14:34:10
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- How to flatten a multidimensional php array?
- There are three common ways to flatten multidimensional arrays. 1. Use recursive traversal to process arrays of any depth, and use is_array() to determine whether to continue in-depth; 2. It is safer to simulate the recursive process in an iterative way, suitable for large data volumes, and use the stack structure to save the elements to be processed; 3. If the array is two-dimensional and the child elements are arrays, it can be implemented concisely with array_merge combined with the expansion operator (...), but it requires support from PHP7.4; in addition, if you need to preserve key values, you can use the merge array by modifying logic.
- PHP Tutorial . Backend Development 386 2025-07-02 14:29:41
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- How to sort php array by value
- In PHP, sorting arrays by value requires selecting different functions according to your needs. 1. Use asort() (ascending order) and arsort() (descending order) to preserve key-value associations, which are suitable for associative arrays; 2. Use sort() (ascending order) and rsort() (descending order) to sort only values ??and reset keys, which are suitable for pure numeric arrays; 3. Use usort() to customize sorting rules, which are suitable for complex structures such as objects or nested arrays, but do not retain the original keys.
- PHP Tutorial . Backend Development 286 2025-07-02 14:29:11
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- How to check if value exists in php array?
- There are three ways to check whether the value exists in PHP array: use in_array() for one-dimensional arrays, such as in_array('banana',$array); use array_search() for key names, such as array_search('Alice',$array); use multi-dimensional arrays, for custom recursive function in_multi_array() for processing. Note that in_array() does not strictly match the type by default. You can add the third parameter true for strict checking, while array_search() results should be judged using !==false to avoid misjudgment.
- PHP Tutorial . Backend Development 927 2025-07-02 14:27:41
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- How to use php array_values
- The array_values ??function is used to extract all values ??in the array and return a new index array. It is suitable for converting associative arrays into digital index arrays, such as processing database results, sorting and filtering data, unified interface formats, etc. The method of using it is to pass in an array, for example $values=array_values($array); it ignores the original key name and generates new indexes starting from 0 in order. Note points include: not modifying the original array, retaining null and empty strings, and not processing deep values ??of multi-dimensional arrays. In practical applications, you can filter the empty value with array_filter and then extract it, or use it with array_merge and rearrange the index.
- PHP Tutorial . Backend Development 861 2025-07-02 14:26:10
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