# Array Slicing in Python

Slicing is used to retrieve set of values from an array.

**Slicing on 1-Dimensional Array**

It is defined as below

arrayName[start:end:step]

start — Starting Index, inclusive. It could be optional as well, default value is 0.

end — Ending Index, exclusive. It could be optional as well, default value is length of the array.

step — Optional field, it is 1 by default.

**Example**

`array1 = [‘a’, ‘b’, ‘c’,’d’,’e’,’f’]`

If we need only the elements b,c,d from the array, then we write as below

`array1[1:4] `

Output: ['b', 'c', 'd']

where 1 is the starting index, 4 is the ending index which is excluded and step is 1 by default.

array1[1:4:2]

Output: ['b', 'd']array1[1:]

Output: ['b', 'c', 'd', 'e', 'f']array1[:4]

Output: ['a', 'b', 'c', 'd']array1[:]

Output: ['a', 'b', 'c', 'd', 'e', 'f']

**Slicing on 2-Dimensional Array**

2D Array consists of rows and columns. So, in order to slice a 2D array, we have to perform slicing operation on both rows and columns. The syntax is as below

`arrayname[start:end:step, start:end:step]`

First one is for rows and second one is for columns

# importing numpy package for creating 2D Array

import numpy as np

#Creating 2D Array

array2 = np.array([[1,2,3,4],

[2,3,4,5],

[3,4,5,6],

[4,5,6,7]

])#Slicing Operation on 2D Array

# to return all rows and only first two columns from the array defined.

array2[:,:2]

Output: array([[1, 2],

[2, 3],

[3, 4],

[4, 5]])

# to return from second row and first two columns

array2[1:,:2]

Output: array([[2, 3],

[3, 4],

[4, 5]])

Happy reading :)