Slicing an array using Indexing in python technology
Python has a slicing feature which allows to access pieces of an array. We, basically, slice an array using a given range (eg. 2nd to 5th position), giving us elements we require. This is done by using indexes separated by a colon [x : y].
fruits = ["Apple", "Banana", "Mango", "Grapes", "Orange"] print(fruits[1:4]) print(fruits[ : 3]) print(fruits[-4:]) print(fruits[-3:-1])
['Banana', 'Mango', 'Grapes'] ['Apple', 'Banana', 'Mango'] ['Banana', 'Mango', 'Grapes', 'Orange'] ['Mango', 'Grapes']
While creating a slice [1:4], slicing starts (inclusive) with left index number, and slicing ends (exclusive) with right index number. This means slicing only prints out the elements of position 1, 2, and 3. Here, position 4 is exclusive so we don’t get Orange as an output.
In the code fruits[:3], you can see we didn’t include the index on the left. This means, slicing takes all elements until the index on the right (excluding the right index), i.e. first 3 (0, 1, 2) elements of the array.
Likewise, fruits[-4:] prints all elements after second position (1 or -4) i.e ‘Banana’. This code is equivalent to fruits[1:].
In the final code, fruits[-3:-1], it all elements starting from index -3 to -2.
Python Array Methods
Other array operations are also available in Python using list/array methods given as:
|append()||to add element to the end of the list|
|extend()||to extend all elements of a list to the another list|
|insert()||to insert an element at the another index|
|remove()||to remove an element from the list|
|pop()||to remove elements return element at the given index|
|clear()||to remove all elements from the list|
|index()||to return the index of the first matched element|
|count()||to count of number of elements passed as an argument|
|sort()||to sort the elements in ascending order by default|
|reverse()||to reverse order element in a list|
|copy()||to return a copy of elements in a list|
All arrays created above are single dimensional. We can also create a multidimensional array in Python. A multidimensional array is an array within an array. This means an array holds different arrays inside it.
Example 10: Create a two-dimensional array using lists
multd = [[1,2], [3,4], [5,6], [7,8]] print(multd) print(multd) print(multd) print(multd)
When we run the above program, the output will be
[1, 2] [7, 8] 6 7