PHP Array Reference

The in_array() function checks if a specific value exists in an array. It returns true if the value is found, or false otherwise.

The array_map() function applies the given callback function to each element of an array and returns a new array. The original array remains unchanged.

The filter() function filters an array, keeping only the values that meet a specified condition. By providing a callback function, it returns a new array containing only the elements that satisfy the condition.

The array_reduce() function iterates through an array using a callback function to repeatedly reduce it to a single value. The original array remains unchanged.

The array_key_exists() function checks if a specified key (or index) exists in an array. It returns true if the key is found, or false otherwise.

The array_keys() function returns a new array containing only the keys (indexes) from the given array. You can either get all keys or selectively extract only the keys that match a specific value.

The array_values() function returns a new array containing all the values from the given array. The returned array uses consecutive numeric indexes starting from 0, and the original keys are ignored.

The array_search() function searches an array for a value. It returns the key (or index) of the first matching element if found, or false if the value is not present.

The array_diff() function finds the differences in array values between two or more arrays and returns a new array containing values that exist only in the first array.

The array_diff_assoc() function compares array differences based on key–value pairs and returns an associative array containing the elements from the first array that are not present in the other arrays.

The array_intersect() function returns an array containing values from the base array that also exist in one or more other arrays.

The array_intersect_assoc() function compares arrays based on key–value pairs and returns the elements from the first array that also exist in the other arrays.

The array_slice() function extracts a specified range of elements from an array and returns the result as a new array.

The array_shift() function removes the first element from an array and returns it. This operation decreases the array's length by one.

The array_merge() function merges one or more arrays in order to create a new array. The elements of each array are appended to the end of the previous array, and the function returns the merged array.

The array_pop() function removes the last element from an array and returns it. This operation decreases the array length by one.

The array_unshift() function prepends one or more elements to the beginning of an array—similar to inserting items at the front. This also increases the array's length.

The array_push() function adds one or more elements to the end of an array—essentially 'pushing' them onto it, like stacking items. This also increases the array's length.

The implode() function joins array elements into a string using a custom delimiter. This function returns a single string by joining each element of a given array with a specified delimiter.