Find length of 2D array Python


Question

How do I find how many rows and columns are in a 2d array?

For example,

Input = ([[1, 2], [3, 4], [5, 6]])`

should be displayed as 3 rows and 2 columns.

1
70
6/30/2016 2:39:25 PM

Accepted Answer

Like this:

numrows = len(input)    # 3 rows in your example
numcols = len(input[0]) # 2 columns in your example

Assuming that all the sublists have the same length (that is, it's not a jagged array).

125
5/23/2012 3:21:34 AM

You can use numpy.shape.

import numpy as np
x = np.array([[1, 2],[3, 4],[5, 6]])

Result:

>>> x
array([[1, 2],
       [3, 4],
       [5, 6]])
>>> np.shape(x)
(3, 2)

First value in the tuple is number rows = 3; second value in the tuple is number of columns = 2.


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