One, custom function
Custom functions are our own defined functions, and the Custom function format in PHP is as follows:
function Funname (arg1, arg2, Arg3 ...) {//todoreturn values;}
<?php function Fun ($m, $n) {if ($m ==0 | | $n ==0) {return 0;} else{$a = $m * $n; return $a;}} $p = 2; $h = 3; echo $p. " * ". $h." = ". Fun ($p, $h);?>
Output Result:
Here's another variable parameter function.
<?php/*function Fun ($m, $n) {if ($m ==0 | | $n ==0) {return 0;} else{$a = $m * $n; return $a;}} $p =2; $h =3;echo $p. " * ". $h." = ". Fun ($p, $h); */function Fun ($m, $n =1, $x =2) {$a = $m * $n * $x; return $a;} $p = 2; echo Fun ($p). " <br> "; 2*1*2 = 4 echo Fun ($p, 3). " <br> "; 2*3*2 = Echo Fun ($p, 3, 3). <br> "; 2*3*3 =?>
Let's see. Custom Function Reference passing
<?php /* Function Fun ($m, $n) { if ($m ==0 | | $n ==0) { return 0; } else{ $a = $m * $n; return $a; } } $p =2; $h =3; echo $p. " * ". $h." = ". Fun ($p, $h); * /* Function Fun ($m, $n =1, $x =2) { $a = $m * $n * $x; return $a; } $p =2; echo Fun ($p). " <br> "; 2*1*2 = 4 echo Fun ($p, 3). " <br> "; 2*3*2 = echo Fun ($p, 3, 3). <br> "; 2*3*3 = /function Fun (& $n) { $n = $n * $n; } $p =2; Fun ($p); echo $p; ? >
Second, array definition assignment
1, array basic writing format
Simple form: Array (value 1, value 2, value 3, ...)
Array ("AA", N, True, 2.2, "test", 50); Get data by array subscript
Full form: Array (key 1=> value 1, key 2=> value 2, ...)
Array ("title" = "AA", "Age" =>20); Data can only be obtained by key name
2. How to create an array
The first $arr 1=array (one, three, three, "seven"); The second $arr 2=array (' a ' = ' one ', ' b ' = ' + '); The third kind of $arr 3[0]= '; $arr 3[1]= ' 30 ';
Three, array operation
1. Modification
$arr =array (one, one, one, one), $arr [0]=55; The array becomes $arr=array (55, 22, 33, 44);
2. Delete
$arr =array (one, one, one, one), unset ($arr [0]); The array becomes $arr=array (22, 33, 44);
3. Use
$arr =array (one, one, one, one), Echo $arr [0]; $arr =array (' A ' =>11, ' B ' =>22, ' C ' =>33, ' d ' =>44); echo $arr [' B ']];
4. Traverse
$arr =array (' A ' =>11, ' B ' =>22, ' C ' =>33, ' d ' =>44); foreach ($arr as $value) {//No key name Echo $value. " <br> ";} foreach ($arr as $id = + $value) { //output key and value echo $id: $value. " <br> ";}
Four or two-d arrays
$arr =array (Array ("1", "one", "111"), Array ("2", "A", "222"), Echo $arr [to];
Five, array functions
(1) array_change_key_case (array, case)
Array: required, arrays.
Case: Optional, Case_lower (default, lowercase returns the key of the array), Case_upper (the key of the array is returned in uppercase letters)
Function: Converts all keys of an array to uppercase or lowercase.
<?php $a =array ("a" = "Cat", "b" = "Dog", "C" and "Horse"); Print_r (Array_change_key_case ($a, case_upper));?> Result: Array ([a] = Cat [B] = Dog [C] = + Horse)
(2) Array_chunk (Array,size,preserve_key)
Array: Required.
Size: Required to specify how many elements each new array includes.
Preserve_key: Optional, True (reserved key name), False (new index)
Function: Divides an array into new array blocks.
<?php //array_chunk (array,size,preserve_key) $a 1=array ("a" and "Cat", "B" and "Dog", "c" = "Horse", "D" = "Cow"); Print_r (Array_chunk ($a)); $a 2=array ("a" = "Cat", "b" = "Dog", "c" = "Horse", "D" and "Cow"); Print_r (Array_chunk ($a 2,2,true)); ? >
Array ([0] = = Array ([0] = Cat [1] = Dog) [1] = = Array ([0] = = Horse [1] = Cow))
Array ([0] = = Array ([a] = Cat [b] = Dog) [1] = = Array ([c] = = Horse [d] = = Cow))
.......
There are many functions like this, which can be checked again when used, and the list is as follows (PHP represents the first version)
function |
Description |
PHP |
Array () |
Creates an array. |
3 |
Array_change_key_case () |
Returns an array whose keys are uppercase or lowercase. |
4 |
Array_chunk () |
Splits an array into a new array block. |
4 |
Array_combine () |
Creates a new array by merging two arrays. |
5 |
Array_count_values () |
Used to count the occurrences of all values in the array. |
4 |
Array_diff () |
Returns an array of difference sets for two arrays. |
4 |
ARRAY_DIFF_ASSOC () |
Compares key names and key values, and returns an array of two arrays of differences. |
4 |
Array_diff_key () |
Compares a key name and returns an array of two array of differences. |
5 |
ARRAY_DIFF_UASSOC () |
The error set of an array is computed by indexing the user-supplied callback function. |
5 |
Array_diff_ukey () |
Use a callback function to compare the difference set of an array to a key name. |
5 |
Array_fill () |
Fills the array with the given value. |
4 |
Array_filter () |
Filters the elements in the array with a callback function. |
4 |
Array_flip () |
Swaps the keys and values in the array. |
4 |
Array_intersect () |
Computes the intersection of an array. |
4 |
ARRAY_INTERSECT_ASSOC () |
Compares the key name and the key value, and returns an array of two arrays of intersections. |
4 |
Array_intersect_key () |
Computes the intersection of an array using the key name comparison. |
5 |
ARRAY_INTERSECT_UASSOC () |
An index check computes the intersection of an array and compares the index with a callback function. |
5 |
Array_intersect_ukey () |
Use the callback function to compare the key names to calculate the intersection of the arrays. |
5 |
Array_key_exists () |
Checks whether the given key name or index exists in the array. |
4 |
Array_keys () |
Returns all the key names in the array. |
4 |
Array_map () |
The callback function is scoped to the cell of the given array. |
4 |
Array_merge () |
Merges one or more arrays into an array. |
4 |
Array_merge_recursive () |
Merges one or more arrays recursively. |
4 |
Array_multisort () |
Sorts multiple arrays or multidimensional arrays. |
4 |
Array_pad () |
Fills the array with a value to the specified length. |
4 |
Array_pop () |
POPs the last cell of the array (out of the stack). |
4 |
Array_product () |
Computes the product of all the values in the array. |
5 |
Array_push () |
Presses one or more cells (elements) into the end of the array (into the stack). |
4 |
Array_rand () |
Randomly selects one or more elements from the array and returns them. |
4 |
Array_reduce () |
Iteratively simplifies the array to a single value using a callback function. |
4 |
Array_reverse () |
Flips the order of elements in the original array, creates a new array, and returns. |
4 |
Array_search () |
Searches the array for the given value and returns the corresponding key name if successful. |
4 |
Array_shift () |
Deletes the first element in the array and returns the value of the deleted element. |
4 |
Array_slice () |
Takes a value out of the array and returns it as a condition. |
4 |
Array_splice () |
Remove parts of the array and replace them with other values. |
4 |
Array_sum () |
Computes the and of all values in the array. |
4 |
Array_udiff () |
Use the callback function to compare the data to calculate the difference set of the array. |
5 |
ARRAY_UDIFF_ASSOC () |
The index check calculates the difference set of the array and compares the data with the callback function. |
5 |
ARRAY_UDIFF_UASSOC () |
The index check calculates the difference set of the array, using the callback function to compare the data and the index. |
5 |
Array_uintersect () |
Computes the intersection of an array and compares the data with a callback function. |
5 |
ARRAY_UINTERSECT_ASSOC () |
With the index check to compute the intersection of the array, compare the data with the callback function. |
5 |
ARRAY_UINTERSECT_UASSOC () |
With an index check computes the intersection of an array, using a callback function to compare data and indexes. |
5 |
Array_unique () |
Removes duplicate values from the array. |
4 |
Array_unshift () |
Inserts one or more elements at the beginning of the array. |
4 |
Array_values () |
Returns all the values in the array. |
4 |
Array_walk () |
Applies a user function to each member in an array. |
3 |
Array_walk_recursive () |
Each member of the array is recursively applied to the user function. |
5 |
Arsort () |
Reverse-Sort an array and maintain an index relationship. |
3 |
Asort () |
Sorts the array and maintains the index relationship. |
3 |
Compact () |
Create an array, including the variable names and their values. |
4 |
Count () |
Calculates the number of elements in an array or the number of attributes in an object. |
3 |
Current () |
Returns the current element in the array. |
3 |
each () |
Returns the current key/value pair in the array and moves the array pointer one step forward. |
3 |
End () |
Points the inner pointer of the array to the last element. |
3 |
Extract () |
Imports a variable from an array into the current symbol table. |
3 |
In_array () |
Checks whether the specified value exists in the array. |
4 |
Key () |
Gets the key name from the associative array. |
3 |
Krsort () |
The array is reversed by key name. |
3 |
Ksort () |
Arrays are sorted by key name. |
3 |
List () |
Assigns the values in the array to some variables. |
3 |
Natcasesort () |
Use the "natural sort" algorithm to sort the case-insensitive letters of an array. |
4 |
Natsort () |
Use the "natural sort" algorithm to sort the array. |
4 |
Next () |
Moves the inner pointer in the array forward one bit. |
3 |
POS () |
The alias of current (). |
3 |
Prev () |
Returns the internal pointer of the array back to one bit. |
3 |
Range () |
Creates an array of elements that contain the specified range. |
3 |
Reset () |
Points the inner pointer of the array to the first element. |
3 |
Rsort () |
Reverse-order an array. |
3 |
Shuffle () |
Rearrange the elements in the array in random order. |
3 |
sizeof () |
The alias of Count (). |
3 |
Sort () |
Sorts the array. |
3 |
Uasort () |
Use a user-defined comparison function to sort the values in the array and keep the index associated. |
3 |
Uksort () |
Use a user-defined comparison function to sort the key names in the array. |
3 |
Usort () |
Use a user-defined comparison function to sort the values in the array. |
3 |