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Copyright by Refsnes Data. All Rights Reserved. W3Schools is Powered by W3. Converting null to an array results in an empty array. Changing the values of the array directly is possible by passing them by reference. Array s are ordered. The order can be changed using various sorting functions.
See the array functions section for more information. The count function can be used to count the number of items in an array. Because the value of an array can be anything, it can also be another array. This enables the creation of recursive and multi-dimensional array s. Array assignment always involves value copying. Use the reference operator to copy an array by reference. Iterables ». Submit a Pull Request Report a Bug. Arrays An array in PHP is actually an ordered map.
Syntax Specifying with array An array can be created using the array language construct. Example 6 Complex Type Casting and Overwriting example This example includes all variations of type casting of keys and overwriting of elements. Accessing array elements with square bracket syntax Array elements can be accessed using the array[key] syntax.
Useful functions There are quite a few useful functions for working with arrays. So why is it bad then? Converting to array For any of the types int , float , string , bool and resource , converting a value to an array results in an array with a single element with index zero and the value of the scalar which was converted.
Examples The array type in PHP is very versatile. Do you like red? Do you like blue? Do you like green? Do you like yellow? For newbies: An array index can be any string value, even a value that is also a value in the array. The value of array["foo"] is "bar". Since PHP 7. Say you have a search function that returns an array of values on success or NULL if nothing found. Note that array value buckets are reference-safe, even through serialization.
Personally I use only square brackets, expect for accessing single char in string. Old habits Bad results can also appear in nested foreach loops the same reason as above. Used to creating arrays like this in Perl? Instead the hashtable means that php takes the given key string and computes from it the memory location of the keyed data, and then instantly retrieves the data.
And so quick. And no need to know anything about hashtables as it's all hidden away. However, there is a lot of overhead in that. It uses lots of memory, as hashtables tend to also nearly doubling on a 64bit server , and should be significantly slower for integer keyed arrays than old-fashioned non-hashtable integer-keyed arrays. This is much quicker. It's also quicker to build the array compared to the complex operations needed for hashtables. And it uses a lot less memory as there is no hashtable data structure.
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