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Array difference function

• The function only checks one dimension in a multi-dimensional array. You can use array_diff($array1[0], $array2[0]) to check deeper dimensions.

• u: Custom function comparison, a(association): Compare keys and values ​​simultaneously .

• The custom function callable $value_compare_func must return an integer that is less than zero, equal to zero, or greater than zero. Returning zero means the two numbers are equal.

Function to compare array values

array_diff

• Comparison (===) array1, The value(value) of array2··· returns the value in $array1 but not in other arrays, and the key name remains unchanged.

array array_diff ( array $array1 , array $array2 [, array $... ] )

array_udiff

• Use custom function to compare $array1, $array2·· ·The value (value), the function parameter is the value of the array. Returns elements in $array1 that are not in other arrays, maintaining key-value association.

array array_udiff ( array $array1 , array $array2 [, array $... ], callable $value_compare_func )

int value_compare_func(( mixed $a, mixed $b )) //该比较函数必须相应地返回一个小于，等于或大于 0 的整数。
#返回0，意味着两个数相等，即值在两个数组都出现了，所以等于0不返回值。
#根据value_compare_func($a, $b)的参数顺序返回元素，如：value_compare_func($b, $ba)，返回在$b不在$a的元素

Function to compare array keys

array_diff_key

• Comparison (===) array1 , keys of array2···, all keys## that appear in $array1 but are not in other arrays # value.

array array_diff_key ( array $array1 , array $array2 [, array $... ] )

• Use custom function to compare

  $array1, $array2·· ·The key, the function parameter is the key of the array, if the key is different, the element will be returned. Returns elements in $array1 that are not in other arrays, maintaining key-value association.

array array_diff_ukey ( array $array1 , array $array2 [, array $... ], callable $key_compare_func )

keys and values

• Compare at the same time

  $array1, $array2···The key and value(value) are returned in $array1 , elements that are not in other arrays maintain key-value associations. .

array array_diff_assoc ( array $array1 , array $array2 [, array $... ] )

• Use custom function to compare

  $array1, $array2·· ·The key(key) and value(value), the callback function parameter is the key of the array, and the element will not be returned when the key values ​​are the same. Returns elements in $array1 that are not in other arrays, maintaining key-value association.

array array_diff_uassoc ( array $array1 , array $array2 [, array $... ], callable $key_compare_func )

• Use custom function to compare

  $array1, $array2·· ·The key(key) and value(value), the callback function parameter is the value of the array, and the element will not be returned when the key values ​​are the same. Returns elements in $array1 that are not in other arrays, maintaining key-value association.

array array_udiff_assoc ( array $array1 , array $array2 [, array $... ], callable $value_compare_func )

• Use custom function to compare

  $array1, $array2·· ·The key(key) and value(value), the two function parameters are the key/value of the array respectively. Returns elements in $array1 that are not in other arrays, maintaining key-value association.

array array_udiff_uassoc ( array $array1 , array $array2 [, array $... ], callable $value_compare_func , callable $key_compare_func )

• The usage of intersection function and difference function are similar

values without comparing keys

• Calculates the intersection of arrays

• Calculate the intersection of arrays and use callback functions to compare data

Keys Function that does not compare values

• Use key name comparison to calculate the intersection of arrays

• Use callback function to compare key names to calculate the intersection of arrays

Keys and Function for value

• Calculate intersection of arrays with index check

• Calculate the intersection of arrays with index checking, use callback function to compare the indexes

• Calculate with index checking Intersection of arrays, using a callback function to compare array values

• Calculates the intersection of arrays with index checking, using a separate callback function to compare data Recommendations related to index

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