numpy.ravel() in Python - GeeksforGeeks

numpy.ravel() in Python

Last Updated : 22 Sep, 2026

The numpy.ravel() function is used to flatten a NumPy array into a one-dimensional array. It returns the elements in the specified order and creates a copy only when required.

Example: Flatten a NumPy Array

Python 
import numpy as np

arr = np.array([[1, 2], [3, 4]])
print(arr.ravel())

Output
[1 2 3 4]

Explanation:

  • np.arange(6) creates an array containing values from 0 to 5.
  • reshape(2, 3) arranges these values into 2 rows and 3 columns.
  • np.ravel(arr) converts the 2D array into a 1D array.
  • The result contains all elements in row-wise order.

Syntax

numpy.ravel(a, order='C')

Parameters: 

  • a - Specifies the input array.
  • order - Specifies the order in which elements are read. It can be 'C', 'F', 'A', or 'K'.

Return Value: Returns a flattened one-dimensional array with the same data type as the input array.

Examples

Example 1: Flatten a 2D Array

The uses ravel() to flatten a two-dimensional NumPy array.

Python 
import numpy as np

arr = np.arange(6).reshape(2, 3)
result = np.ravel(arr)

print(result)

Output
[0 1 2 3 4 5]

Explanation:

  • np.arange(6) creates values from 0 to 5.
  • reshape(2, 3) arranges the values into 2 rows and 3 columns.
  • np.ravel(arr) converts the 2D array into a 1D array.
  • The elements are returned in row-wise order by default.

Example 2: Using C and F Order

The shows how the order parameter affects the arrangement of elements.

Python 
import numpy as np

arr = np.array([[1, 2, 3], [4, 5, 6]])

print("C order:", arr.ravel(order='C'))
print("F order:", arr.ravel(order='F'))

Output
('C order:', array([1, 2, 3, 4, 5, 6]))
('F order:', array([1, 4, 2, 5, 3, 6]))

Explanation:

  • order='C' reads the elements row-wise.
  • order='F' reads the elements column-wise.
  • C order returns [1, 2, 3, 4, 5, 6].
  • F order returns [1, 4, 2, 5, 3, 6].

Example 3: Using A Order

The uses 'A' order to determine the element order based on the array's memory layout.

Python 
import numpy as np

arr = np.array([[1, 2], [3, 4]])
print(arr.ravel(order='A'))

Output
[1 2 3 4]

Explanation:

  • order='A' checks the memory layout of the array.
  • It uses Fortran-style ordering if the array is Fortran-contiguous.
  • Otherwise, it uses C-style ordering.
  • The given array uses C-style ordering, so the result is [1, 2, 3, 4].

Example 4: Using K Order

The uses 'K' order to preserve the elements according to their memory layout.

Python 
import numpy as np

arr = np.arange(12).reshape(2, 3, 2).swapaxes(1, 2)

print(arr)
print(arr.ravel(order='K'))

Output
[[[ 0  2  4]
  [ 1  3  5]]

 [[ 6  8 10]
  [ 7  9 11]]]
[ 0  1  2  3  4  5  6  7  8  9 10 11]

Explanation:

  • np.arange(12) creates values from 0 to 11.
  • reshape(2, 3, 2) creates a three-dimensional array.
  • swapaxes(1, 2) changes the positions of the second and third axes.
  • ravel(order='K') reads the elements according to their memory layout.
  • The result is a one-dimensional array containing all elements.

Note : These codes won’t run on online IDE's. Please run them on your systems to explore the working.

Comment

Explore