PHP Learning Notes-Arrays (12)

each (array);

Role:

Returns the key and value for the current array, and moves the inner pointer forward.

Parameters:

Array: Arrays

return value:

Returns the current element

Example: use each to return each value of an array

$a = Array (' a ' = = ' red ', ' b ' = ' blue ', ' c ' = ' yellow '); while (list ($key, $value) = each ($a)) {echo "$key $value \ n";} Output: A->redb->bluec->yellow

End (array);

Role:

Point an internal pointer to the last element

Parameters:

Array: Arrays

return value:

Successfully returns the value of the last element, failure returns false

Example: The last parameter of an output array

$a = Array (' a ' = = ' red ', ' b ' = ' blue ', ' c ' = ' yellow '); $res = end ($a);  Print_r ($res); Output Result: Yellow

Extract (array, extract_rules, prefix)

Role:

Use the array's key as the variable, and the value of the array as the variable

Parameters:

Array: Arrays

Extract_rules:

Optional. The extract () function checks to see if each key name is a valid variable name, and also checks to see if the variable name already exists in the symbol table conflicts. The handling of non-law and conflicting key names is determined by this parameter.

Possible values:

• Extr_overwrite-Default. If there is a conflict, overwrite the existing variable.

• Extr_skip-If there is a conflict, do not overwrite the existing variable.

• Extr_prefix_same-If there is a conflict, precede the variable name with the prefix PREFIX.

• Extr_prefix_all-Prefix all variable names with PREFIX.

• Extr_prefix_invalid-Prefix PREFIX only before the illegal or numeric variable name.

• Extr_if_exists-Overrides the value of a variable with the same name in the current symbol table only. None of the others will deal with it.

• Extr_prefix_if_exists-A variable name with the prefix appended to it is created only if a variable with the same name already exists in the current symbol table, and none of the others are processed.

• Extr_refs-Extracts the variable as a reference. The imported variable still references the value of the array parameter.

Prefix

Optional. Extr_prefix_if_exists is required if the value of the Extract_rules parameter is Extr_prefix_same, Extr_prefix_all, Extr_prefix_invalid, or PREFIX.

This parameter specifies the prefix. An underscore is automatically added between the prefix and the array key name.

return value:

Returns the number of variables that were set successfully.

Example:

1, the array key as the variable name $a = Array (' a ' = ' = ' red ', ' b ' = ' blue ', ' c ' = ' yellow '); $res = extract ($a);  echo "$a \n$b\n$c\n"; Output: Red blue yellow 2, the array key as the variable name and add a prefix $a = array (' a ' = ' = ' red ', ' b ' = = ' blue ', ' c ' = ' yellow '); $res = Extract ($a, extr_prefix_all, ' my ');  echo "$my _a\n$my_b\n$my_c\n"; Output result: Red Blue Yellow

In_array (value, array, strict);

Role:

Finds if value exists in array

Parameters:

Value: values that need to be looked up

Array: Arrays

Strict: optional, default feed false, if the True,value value needs to be the same as the type and value of the values in the array

return value:

Existence returns TRUE, Failure returns false

Example: whether the number 12 exists in an array

$a = Array (' a ' = = ' red ', ' b ' = ' blue ', ' c ' = ' 12 ');  if (In_array ($a, true)) {echo ' exists ';} else {echo ' does not exist ';} Output result: not present

Key (array);

Role:

Gets the key for the internal pointer of the current array

Parameters:

Array: Arrays

return value:

Returns the key of the inner pointer in the array

Example:

$a = Array (' a ' = = ' red ', ' b ' = ' blue ', ' c ' = ' 12 '); $res = key ($a);  Print_r ($res); Output Result: A

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PHP Learning Notes-Arrays (12)