Summary of use examples of array processing functions in PHP

Summary of use examples of array processing functions in PHP

# Changing the case sensitivity of the array key $ Arr1 = array ("a" => "Lamp", "db" => "database", "LANGUAGE" => "PHP "); Print_r (array_change_key_case ($ arr1, CASE_UPPER )); Echo" "; Print_r (array_change_key_case ($ arr1, CASE_LOWER )); Echo" "; # Split an array into multiple third parameters to set whether to retain the key $ Arr2 = array ('A', 'B', 'C', 'D', 'e', 'F', 'g '); Print_r (array_chunk ($ arr2, 2, true )); Echo" "; Print_r (array_chunk ($ arr2, 2, false )); Echo" "; # Array array_diff_assoc (array $ array1, array $ array2 [, array $...]) returns an array, # This array includes all the values in the array of array1 but not in any other parameter array. # Different keys $ Arr3 = array ('a' => 'green', 'B' => 'brown ', 'C' => 'red '); $ Arr4 = array ('a' => 'green', 'yellow', 'red '); Print_r (array_diff_assoc ($ arr3, $ arr4 )); Echo" "; # Array_diff (array $ array1, array $ array2 [, array $...]) # Returns an array that contains all but not any # The values in other parameter arrays are not counted if the keys are different. Print_r (array_diff ($ arr3, $ arr4 )); Echo" "; # Array_fill (int $ start_index, int $ num, mixed $ value) # Use the value of the value parameter to fill an array with num entries, # The key name is specified by the start_index parameter. Print_r (array_fill (-5, 8, "banana ")); Echo" "; # Array_flip (array $ trans) # Returns an inverted array. for example, the key name in trans is changed to a value, # The value in trans is the key name. $ Arr5 = array ('a' => '1', "B" => "2", "c", "d", "e "); Print_r (array_flip ($ arr5 )); Echo" "; # Array_map (callback $ callback, array $ arr1 [, array $...]) # Returns an array containing all the elements in arr1 that have passed the callback function # Subsequent units. The number of parameters accepted by callback should be passed to array_map () # The number of functions is the same. Function cube ($ n ){ Return $ n * $ n; } $ Arr6 = array (1, 2, 3, 4, 5 ); Print_r (array_map ("cube", $ arr6 )); Echo" "; # Array_merge_recursive (array $ array1 [, array $...]) # Merge the units of one or more arrays. the values in an array are appended to the previous array. . Returns an array of results. If the input array has the same string key name, # Then these values will be merged into an array, which will be recursive, so if a value itself # Is an array. this function combines it into another array according to the corresponding entries. However, for example # If the array has the same array key name, the next value will not overwrite the original value, but will be appended . $ Arr7 = array ("color" => array ("favorite" => "red"), 5 ); $ Arr8 = array (10, array ("favorite" => "yellow", "blue ")); Print_r (array_merge_recursive ($ arr7, $ arr8 )); Echo" "; # Array_reduce (array $ input, callback $ function [, int $ initial] # Iterate the callback function to every unit in the input array, so that the array # Simplified to a single value. If the optional parameter initial is specified, the parameter is treated as # Process a value, or use the final return value if the array is empty. If the array is empty and no # If the initial parameter is passed, array_reduce () returns NULL. Function rsum ($ v, $ w ){ $ V + = $ w; Return $ v; } Function rmul ($ v, $ w ){ $ V * = $ w; Return $ v; } $ A = array (1, 2, 3, 4, 5 ); $ X = array (); $ B = array_reduce ($ a, "rsum "); $ C = array_reduce ($ a, "rmul", 10 ); $ D = array_reduce ($ x, "rsum", 1 ); Echo $ B. "\ t". $ c. "\ t". $ d. "\ n "; Echo" "; # Array_replace (array & $ array, array & $ array1 [, array & $ array2 [, array & $...]) # The function replaces the value of the first array with the value of the following array element. If a key exists in the first # An Array also exists in the second array, and its value will be replaced by the value in the second array. If # If the key exists in the second array but does not exist in the first array, this # Element. If a key only exists in the first array, it remains unchanged. If multiple replicas are passed # Groups, which are processed sequentially, and the subsequent arrays overwrite the previous values. $ Base = array ("orange", "banana", "apple", "raspberry "); $ Replacements = array (0 => "pineapple", 4 => "cherry "); $ Replacements2 = array (0 => "grape "); # Print_r (array_replace ($ base, $ replacements, $ replacements2 )); # Echo" "; # Array_splice (array & $ input, int $ offset [, int $ length [, array $ replacement]) # Remove the units specified by offset and length from the input array. if replacement is provided # Parameter, which is replaced by cells in the replacement array. Returns an array containing the removed cells. #. Note that the number key name in input is not retained. If length is omitted, remove # Offset all parts to the end. If length is specified and it is a positive value, so many units are removed. #. If length is specified and it is a negative value, remove the reciprocal length from offset to the end of the array. # All units in the middle. Tips: remove from offset # Count ($ input) is used as the length for all cells at the end of the array. $ Input = array ("red", "green", "blue", "yellow "); Array_splice ($ input, 1,-1 ); Print_r ($ input ); Echo" "; # Key (array & $ array) # Return the key name of the current cell in the array. $ Fruit = array ("fruit1" => "apple", "fruit2" => "orange", "fruit3" => "grape ", "Fruit4" => "apple", "fruit5" => "apple "); While ($ fruit_name = current ($ fruit )){ If ($ fruit_name = 'apple '){ Echo key ($ fruit )." "; } Next ($ fruit ); } Echo" "; ?>

PHP