To get the length of a 2D Array in Python, you can use numpy.array.size property or use len() function. Let follow the article below.
Get the length of a 2D Array in Python
The array is a data structure to store elements. The index of the array starts at 0, and the last index is equal to the number of array elements minus 1.
A two-dimensional array consisting of two elements: rows and columns.
Syntax:
[[ r1, r2, r3, .., rn ], [ c1, c2, c3, ......., cn ]]
Parameters:
- r: are the rows of the array.
- c: are the columns of the array.
Example:
myArray= [[1,2,3], [4,5,6], [7,8,9]]Array ‘myArray’ consists of 4 rows and 5 columns.
To get the length of a 2D Array in Python, I have the following ways:
Use numpy.array.size property
In this case, I use the numpy.array.size property to find the length of a 2D array. To use it, you need to declare the Numpy library.
Example:
- Create a 2D array.
- Create arrays using numpy.
- Use the array.size function to calculate the size of the array.
import numpy as np
myArray = ([[1,2,3], [4,5,6], [7,8,9]])
numpyArr = np.array([[1,2,3], [4,5,6], [7,8,9]])
# Use the array.size to get the size of the array
print("Size of the 2D array: ", numpyArr.size)Output:
Size of the 2D array: 9Use len() function
To find the length of a 2D array you can use the len() function.
Syntax:
len(object)
Parameters:
- object: an object for which you want to calculate the length. That object can be a string, bytes, tuple, list, range, dictionary, set, or frozen set. Specifically, in this case, a 2-dimensional array.
The len() function returns the number of characters of the input string.
Example:
- Create 2D array.
- Use len() function to calculate the number of rows.
- Use len() function to calculate the number of columns.
- Size of 2D array = rows * columns.
myArray = [[1,2,3], [4,5,6], [7,8,9]]
rowSize = len(myArray)
columnSize = len(myArray[0])
print("Size of 2D array: ", columnSize * rowSize)Output:
Size of 2D array: 9Use the ‘shape’ property
Another way to find the length of a 2D array is to use the ‘numpy.shape’ property.
Example:
- Create a 2D array.
- Create arrays using numpy.
- The ‘shape’ property returns the set of dimensions of array 2D (rows and columns).
- Size of 2D array = rows * columns.
import numpy as numpy
numpyArray = numpy.array([[1,2,3], [4,5,6], [7,8,9]])
print('Number of rows and columns ', numpy.shape(numpyArray))
# The 'shape' property returns the set of dimensions of array 2D (rows and columns)
cols, rows = numpyArray.shape
lenOf2DArray = rows * cols
print("The length of 2D Array :", lenOf2DArray)Output:
Number of rows and columns (3, 3)
The length of 2D Array : 9Summary
If you don’t know how to get the length of a 2D Array in Python, let leave a comment below. I will answer your questions. Thank you for reading!
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My name is Jason Wilson, you can call me Jason. My major is information technology, and I am proficient in C++, Python, and Java. I hope my writings are useful to you while you study programming languages.
Name of the university: HHAU
Major: IT
Programming Languages: C++, Python, Java
