Summary of array processing functions in PHP

? Php # change the case sensitivity of the array key $ arr1array (aLamp, dbdatabase, LANGUAGEPHP); print_r (array_change_key_case ($ arr1, CASE_UPPER); echobr; print_r (array_change_key_case, CASE_LOWER); echohrbr; # split an array into multiple third parameters and set whether to retain the key

? Php # change 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 br /; print_r (array_change_key_case ($ arr1, CASE_LOWER); echo hrbr/; # split an array into multiple third parameters to set whether to retain the key

# 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"
";
?>