Python NumPy tile

The python numpy tile function repeats the array elements for a given number of times and constructs a new array. This method will consider the input array as a tile or piece and repeat for a given number of times vertically and horizontally.

numpy.tile(arr, repetition)

This Python numpy tile method will return a 1D, 2D, 3D or multi-dimensional array based on the d value or length of a given ndarray. To understand better, consider the length of a given array as d.

• If repetition is a single scalar value, arr will repeat for d times, and the output dimension = max(d, arr.ndim). For instance, if arr is one-dimensional, the output will be 1D, if arr is two-dimensional, the output will be 2D, etc.
• If arr.ndim < d, the output dimension = d.
• If arr.ndim > d, the output dimension = arr.ndim.

Python NumPy tile Example

In this program, we declared an array of three numbers. For the b variable, the repetition value is 2, so 1, 2, and 3 will repeat twice. The next one will repeat thrice.

import numpy as np

a  = np.array([1, 2, 3])

b = np.tile(a, 2)
print(b)

c = np.tile(a, 3)
print(c)

[1 2 3 1 2 3]
[1 2 3 1 2 3 1 2 3]

Example 2

In this example, we use the multiple values as the repetition argument. So, the below examples will convert the one-dimensional array to 2D and 3D.

import numpy as np

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

b = np.tile(a, (2, 2))
print(b)

c = np.tile(a, (3, 2))
print(c)

d = np.tile(a, (4, 1))
print(d)

e = np.tile(a, (2, 1, 3))
print(e)

[[1 2 3 4 1 2 3 4]
 [1 2 3 4 1 2 3 4]]

[[1 2 3 4 1 2 3 4]
 [1 2 3 4 1 2 3 4]
 [1 2 3 4 1 2 3 4]]

[[1 2 3 4]
 [1 2 3 4]
 [1 2 3 4]
 [1 2 3 4]]

[[[1 2 3 4 1 2 3 4 1 2 3 4]]

 [[1 2 3 4 1 2 3 4 1 2 3 4]]]

np.tile(a, (3, 2))

d = len(reps) = 2

ndim = 1

max(2, 1) = 2 = d, so it returns the array of 3 columns, and arr values will repeat two times.

np.tile(a, (2, 1, 3)) means block size = 2, and each dimension has single dimensional array. The ndarray values in each dimension will repeat three times.

Python numpy two Dimensional tile

For two-dimensional array inputs, consider the 2D array as a single item.

a, (3, 2) = The whole 2D array will repeat vertically 3 times and horizontally two times.

np.tile(a, (2, 3, 4)) = 2D array will convert to 3D where block size = 2. On each block, the 2D array (a) will repeat vertically three times and horizontally four times.

import numpy as np

a  = np.arange(4).reshape(2, 2)
print(a)

b = np.tile(a, (3, 2))
print(b)

c = np.tile(a, (2, 2, 3))
print(c)

d = np.tile(a, (2, 3, 4))
print(d)

[[0 1]
 [2 3]]

[[0 1 0 1]
 [2 3 2 3]
 [0 1 0 1]
 [2 3 2 3]
 [0 1 0 1]
 [2 3 2 3]]

[[[0 1 0 1 0 1]
  [2 3 2 3 2 3]
  [0 1 0 1 0 1]
  [2 3 2 3 2 3]]

 [[0 1 0 1 0 1]
  [2 3 2 3 2 3]
  [0 1 0 1 0 1]
  [2 3 2 3 2 3]]]

[[[0 1 0 1 0 1 0 1]
  [2 3 2 3 2 3 2 3]
  [0 1 0 1 0 1 0 1]
  [2 3 2 3 2 3 2 3]
  [0 1 0 1 0 1 0 1]
  [2 3 2 3 2 3 2 3]]

 [[0 1 0 1 0 1 0 1]
  [2 3 2 3 2 3 2 3]
  [0 1 0 1 0 1 0 1]
  [2 3 2 3 2 3 2 3]
  [0 1 0 1 0 1 0 1]
  [2 3 2 3 2 3 2 3]]]

The next two examples will show you how to tile the numpy array horizontally and vertically.

tile Horizontally

import numpy as np

a  = np.arange(5)

b = np.tile(a, (3, 1))
print(b)

c = np.arange(4).reshape(2, 2)
print(c)

d = np.tile(c, (4, 1))
print(d)

[[0 1 2 3 4]
 [0 1 2 3 4]
 [0 1 2 3 4]]

[[0 1]
 [2 3]]
[[0 1]
 [2 3]
 [0 1]
 [2 3]
 [0 1]
 [2 3]
 [0 1]
 [2 3]]

tile Vertically

import numpy as np

a  = np.arange(5)

b = np.tile(a, (4))
print(b)

c = np.arange(4).reshape(2, 2)
print(c)

d = np.tile(c, (1, 4))
print(d)

[0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4]

[[0 1]
 [2 3]]

[[0 1 0 1 0 1 0 1]
 [2 3 2 3 2 3 2 3]]