The length of 2d array in python is the number of rows in it. Generally 2d array has rows with same number of elements in it.
Consider an example, array = [[10,20,30], [40,50,60]].
Length of array is 2.

Number of rows in 2d array

Use len(arr) to find the number of row from 2d array. To find the number columns use len(arr[0]). Now total number of elements is rows * columns.

Example:

Consider a 2d array arr = [[20,30,40], [50,60,70]].
Here len(arr) will return 2.
len(arr[0]) will return 3, as it has three columns.

Program:

array = [[100,200,300], [400,500,600]]

#get the number of rows
rows = len(array)

#get the number of columns
cols = len(array[0])

print('Length is', rows)
print('Number of columns', cols)
print('Total number of elements', rows * cols)

Output:

Length is 2
Number of columns 3
Total number of elements 6

Find length of 2d array using numpy

To find the length of 2d array we can use numpy.shape. This function returns number of rows and columns.

Program:

import numpy as numpy
arr_representation = numpy.array([[60, 70],[80, 90],[100, 200]])
print('Number of (rows,cols)', numpy.shape(arr_representation))

Output:

Number of (rows,cols) (3, 2)