Find length of 2D array Python
PythonArraysPython Problem Overview
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.
Python Solutions
Solution 1 - Python
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).
Solution 2 - Python
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.
Solution 3 - Python
In addition, correct way to count total item number would be:
sum(len(x) for x in input)
Solution 4 - Python
Assuming input[row][col],
rows = len(input)
cols = map(len, input) #list of column lengths
Solution 5 - Python
You can also use np.size(a,1), 1 here is the axis and this will give you the number of columns
Solution 6 - Python
assuming input[row][col]
rows = len(input)
cols = len(list(zip(*input)))