What is disk defragmentation? Array operation function defragmentation in php

Array([key =>] value, [key =>] value, [key =>] value, [key =>] value) // key can be integer or string // value can be any value
array_change_key_case -- Returns an array whose string keys are all lowercase or uppercase
array_chunk -- Split an array into multiple
array_combine -- Create an array, using the value of one array as its key name, 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 -- Calculate the difference of the array with index checking
array_diff_key -- Calculate the difference of the array using key name comparison
array_diff_uassoc -- Use a user-provided callback The function does index checking to calculate the difference of the array
array_diff_ukey -- Computes the difference of the array using the callback function to compare the key names
array_diff -- Calculates the difference of the array
array_fill -- Fills the array with the given value
array_filter -- Use the callback function to filter the cells in the array
array_flip -- Exchange keys and values ​​in the array
array_intersect_assoc -- Calculate the intersection of arrays with index checking
array_intersect_key -- Calculate the intersection of arrays using key name comparison
array_intersect_uassoc -- Calculate with index checking Intersection of arrays, use callback function to compare indices
array_intersect_ukey -- Use callback function to compare key names to calculate the intersection of arrays
array_intersect -- Calculate intersection of arrays
array_key_exists -- Check whether the given key name or index exists in the array
array_keys -- Returns all the 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 multi-dimensional arrays
array_pad -- Pad the array to the specified length with values ​​
array_pop -- Pop the last element of the array
array_product -- Calculate the product of all values ​​in the array
array_push - - Push one or more elements to the end of the array (push)
array_rand -- Randomly take one or more elements from the array
array_reduce -- Use a callback function to iteratively reduce the array to a single value
array_reverse -- Return an array with the cells in reverse order
array_search -- Search for a given value in the array, 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 the array and replace it with other values ​​
array_sum -- Calculate the sum of all values ​​​​in the array
array_udiff_assoc -- Calculate the difference of the array with index check, use the callback function to compare the data
array_udiff_uassoc -- Calculate the array with index check The difference set, use the callback function to compare the data and the index
array_udiff -- Use the callback function to compare the data to calculate the difference set of the array
array_uintersect_assoc -- Calculate the intersection of the arrays with index check, use the callback function to compare the data
array_uintersect_uassoc -- With the index check Calculate the intersection of arrays, use callback functions to compare data and indexes
array_intersect -- Calculate the intersection of arrays, use callback functions to compare data
array_unique -- Remove duplicate values ​​in the array
array_unshift -- Insert one or more cells at the beginning of the array
array_values ​​-- Return all values ​​in the array
array_walk_recursive -- Recursively apply a user function to each member of the array
array_walk -- Apply a user function to each member of the 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 (sizeof) -- Count the number of cells in the array or Number of attributes in the object
current -- Returns the current unit in the array
each -- Returns the current key/value pair in the array and moves the array pointer forward one step
end -- Points the internal pointer of the array to the last unit
extract -- Import variables from the array 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 in reverse order by key name
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 in a case-insensitive manner
natsort -- Use the "natural sort" "Algorithm to sort the arraynext -- Move the internal pointer in the array forward by one
pos -- Alias ​​of current() prev -- Move the internal pointer of the array back by one range -- Create a range containing the specified range unit Array

The above has introduced what is disk defragmentation and the defragmentation of array operation functions in PHP, including what is disk defragmentation. I hope it will be helpful to friends who are interested in PHP tutorials.