Compiled a comprehensive list of array operations in PHP development, including basic functions of array operations, array segmentation and filling, arrays and stacks, arrays and queues, callback functions, sorting, calculations, and other arrays functions etc.
1. Basic functions of array operations
The key name and value of the array
array_values($arr); Obtain the array The value of
array_keys($arr); Get the key name of the array
array_flip($arr); The value in the array is interchanged with the key name (if there are duplicates, the previous one will be overwritten by the later one)
in_array ("apple",$arr); Search for apple in the array
array_search("apple",$arr); Search for apple in the array and return the key name if it exists
array_key_exists("apple",$arr) ; Retrieve whether the given key name exists in the array
isset($arr[apple]): Retrieve whether the given key name exists in the array
Internal pointer of the array
current ($arr); Returns the current unit in the array
pos($arr); Returns the current unit in the array
key($arr); Returns the key name of the current unit in the array
prev($arr ); Move the internal pointer in the array back one bit
next($arr); Move the internal pointer in the array forward one bit
end($arr); Point the internal pointer in the array to the last one Unit
reset($arr; points the internal pointer in the array to the first unit
each($arr); will return a constructed array of key names/values of the current element of the array, and move the array pointer forward Move one bit
list($key,$value)=each($arr); Get the key name and value of the current element of the array
Conversion between arrays and variables
extract( $arr); is used to convert the elements in the array into variables and import them into the current file. The key name is used as the variable name and the value is used as the variable value
Note: (The second parameter is very important, you can refer to the manual for use) Use Method echo $a;
compact(var1,var2,var3);Creates an array with the given variable name
2. Array segmentation and filling
Segmentation of array
array_slice($arr,0,3); You can take out a section of the array. This function ignores the key name
array_splice($arr,0,3,array(" black","maroon")); You can take out a section of the array. The difference from the previous function is that the returned sequence is deleted from the original array
Split multiple arrays
array_chunk($ arr,3,TRUE); You can split an array into multiple, TRUE is to retain the key name of the original array
Filling of the array
array_pad($arr,5,'x') ; Fill an array to the specified length
3. Array and Stack
array_push($arr,"apple","pear"); Push one or more elements into the end of the array stack (push) , return the number of elements pushed into the stack
array_pop($arr); Pop the last element of the array stack(pop the stack)
4. Arrays and queues
array_shift($arr);The first element in the array is moved out and returned as the result (the length of the array is reduced by 1, other elements are moved forward by one position, the numeric key name is changed to zero, and the text key name remains unchanged)
array_unshift($arr,"a",array(1,2));Insert one or more elements at the beginning of the array
5. Callback function
array_walk($arr,'function','words'); Use user function to process each member in the array (the third parameter is passed to the callback function function)
array_mpa("function",$arr1, $arr2); can handle multiple arrays (when using two or more arrays, their lengths should be the same)
array_filter($arr,"function"); Use the callback function to filter each element in the array, If the callback function is TRUE, the current element of the array will be included in the returned result array, and the key names of the array will remain unchanged
array_reduce($arr,"function","*"); converted into a single-valued function ( * is the first value of the array)
6. Sorting of the array
Sort the array by element value
sort($arr); Sort in order from small to large (the second parameter is how to sort) Array sorting ignoring key names
rsort($arr); Sort in order from large to small (the second parameter is how to sort) ) Array sorting ignoring key names
usort($arr,"function"); Use a user-defined comparison function to sort the values in the array (there are two parameters in the function, 0 means equal, and a positive number means the first One is greater than the second, a negative number means the first is less than the second) Array sorting ignoring the key name
asort($arr); Sort from small to large (the second parameter is how to sort) Array sorting with key names preserved
arsort($arr); Sorting from large to small (the second parameter is the sorting method) Array sorting with key names preserved
uasort($arr,"function" ); Use a user-defined comparison function to sort the values in the array (there are two parameters in the function, 0 means equal, a positive number means the first is greater than the second, a negative number means the first is less than the second) reserved Array sorting of key names
Sort the array by key names
ksort($arr); Sort by key names in positive order
krsort($arr); Sort by key names in reverse order
uksort($arr,"function"); Use a user-defined comparison function to sort the keys in the array (there are two parameters in the function, 0 means equal, a positive number means the first one is greater than the second one, Negative number means the first one is smaller than the second one)
Natural sorting method
natsort($arr); Natural sorting (ignore key names)
natcasesort($arr); Natural sorting (ignore case, ignore key names)
7. Array calculations
Sum of array elements
array_sum($arr); Perform sum operation on all elements inside the array
Merge of arrays
array_merge($arr1,$arr2); Merge two or more arrays (the same string key name, the latter one overwrites the previous one, the same numeric key name, the latter one will not be overwritten, but appended to the end )
“+”$arr1+$arr2; For the same key name, only the last one is retained
array_merge_recursive($arr1,$arr2); Recursive merge operation, if there are the same string key names in the array, these values will be merged into an array. If a value itself is an array, it will be merged into another array according to the corresponding key name. When arrays have the same array key name, the latter value will not overwrite the original value, but will be appended to the difference set of the following
array_diff($arr1,$arr2) ; Returns the difference set result array
array_diff_assoc($arr1,$arr2,$arr3); Returns the difference set result array, and the key names are also compared
Intersection of the arrays
array_intersect($ arr1,$arr2); Returns the intersection result array
array_intersect_assoc($arr1,$arr2); Returns the intersection result array, the key names are also comparedrange(0,12); Create an array containing the specified range of cells
array_unique($arr); Remove duplicate values in the array, and the original key names will be retained in the new arrayarray_reverse($arr,TRUE); Returns an array with the order of cells reversed to the original array. If the second parameter is TRUE, the original key name is retained.
//srand((float)microtime()*10000000); Random Seed trigger
array_rand($arr,2); Randomly remove one or more elements from the array
shuffle($arr); Shuffle the order of the array
This class of functions allows Multiple ways to manipulate and interact with arrays. The essence of an array is to store, manage and operate a set of variables.
PHP supports one- and multi-dimensional arrays, which can be created by the user or by another function. There are specific database processing functions that generate arrays from database queries, and there are functions that return arrays.
array_change_key_case — Returns an array whose string keys are all lowercase or uppercase
array_chunk — Splits an array into multiples
array_combine — Create an array with the value of one array as its key and the value of another array as its value
array_count_values — Count the number of occurrences of all values in the array
array_diff_assoc — Compute the difference of an array with index checking
array_diff_key — Compute the difference of an array using key name comparison
array_diff_uassoc — Compute the difference of an array with an index check using a user-supplied callback function
array_diff_ukey — Use callback function to compare key names to calculate the difference set of arrays
array_diff — Calculate the difference set of arrays
array_fill_keys — Fill an array with values, specifying keys
array_fill — fills an array with given values
array_filter — uses a callback function to filter elements in an array
array_flip — swaps keys and values in an array
array_intersect_assoc — Computes the intersection of arrays with index checking
array_intersect_key — Computes the intersection of arrays using key name comparison
array_intersect_uassoc — Computes the intersection of arrays with index checking, compares the indices with a callback function
array_intersect_ukey — Calculate the intersection of arrays using callback functions to compare keys
array_intersect — Calculate the intersection of arrays
array_key_exists — Check whether a given key or index exists in an array
array_keys — Returns all keys in the array
array_map — Apply the callback function to the cells of the given array
array_merge_recursive — Recursively merge one or more arrays
array_merge — Merge one or more arrays
array_multisort — Sort multiple arrays or multidimensional arrays
array_pad — Pad the array with values to the specified length
array_pop — Pop the last element of the array
array_product — Calculate the product of all values in an array
array_push — Push one or more elements to the end of the array (push)
array_rand — Take a random element from the array or multiple cells
array_reduce — Use a callback function to iteratively reduce an array to a single value
array_reverse — Return an array with the cells in reverse order
array_search — Within an array Search for the given value, and return the corresponding key name if successful
array_shift — Move the unit at the beginning of the array out of the array
array_slice — Remove a segment from the array
array_splice — Remove part of an array and replace it with another value
array_sum — Calculate the sum of all values in an array
array_udiff_assoc — Calculate the difference of an array with index checking, compare data using callback functions
array_udiff_uassoc — Computes the difference of an array with index checking, using a callback function to compare data and indexes
array_udiff — Computes the difference of an array using a callback function to compare data
array_uintersect_assoc — With indexing Check to calculate intersection of arrays, compare data using callback function
array_uintersect_uassoc — Check to calculate intersection of arrays with index, use callback function to compare data and index
array_uintersect — Calculate intersection of arrays, use callback function Compare data
array_unique — Remove duplicate values in an array
array_unshift — Insert one or more cells at the beginning of an array
array_values — Returns all values in an array
array_walk_recursive — Recursively applies a user function to each member of an array
array_walk — Applies a user function to each member of an array
array — Create a new array
arsort — Sort the array in reverse and maintain the index relationship
asort — Sort the array and maintain the index relationship
compact — Create an array, including variable names and their values
count — Count the number of cells in the array or the number of attributes in the object
current — Return the current cell in the array
each — Returns the current key/value pair in the array and moves the array pointer one step forward
end — Points the array’s internal pointer to the last element
extract — Extracts the array pointer from the array Import variables into the current symbol table
in_array — Check whether a certain value exists in the array
key — Get the key name from the associative array
krsort — Sort the array according to the key Name reverse sort
ksort — Sort the array by key name
list — Assign the values in the array to some variables
natcasesort — Use the “natural sort” algorithm to sort the array Perform a case-insensitive sort
natsort — Sort an array using the “natural sort” algorithm
next — Move the internal pointer in the array forward one position
pos — Alias for current()
prev — Rewind the internal pointer of an array by one position
range — Create an array containing cells in the specified range
reset — Point the internal pointer of the array to the first cell
rsort — Sort the array in reverse order
shuffle — Shuffle an array
sizeof — Alias for count()
sort — Sort an array
uasort — Use a user-defined comparison function to compare values in an array Sort and maintain index correlation
uksort — Sort the keys in an array using a user-defined comparison function
usor — Sort the values in an array using a user-defined comparison function
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