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Copyright 1999-2022 by Refsnes Data. All Rights Reserved. Hey, folks! I hope you all are doing well. In this article, we will be unveiling 3 variants of Array length in Python. As we all know, Python does not support or provide us with the array data structure in a direct manner. Instead, Python serves us with 3 different variants of using an Array data structure here. Let us go first go through the different ways in which we can create a Python array. Further, in the upcoming sections, we would be discussing about use of Python len() method to fetch the length of array in each of the variants. Finding the Array Length in Python using the len() methodPython provides us with the array data structure in the below forms:
We can create an array using any of the above variants and use different functions to work with and manipulate the data.
Syntax: Let us now understand the way to find out the length of an array in the above variants of Python array. Finding the Length of a Python List
In the below example, we have created a list of heterogeneous elements. Further, we have used len() method to display the length of the list. lst = [1,2,3,4,'Python']
print("List elements: ",lst)
print("Length of the list:",len(lst))
Output: List elements: [1, 2, 3, 4, 'Python'] Length of the list: 5 Finding the Length of a Python Array
import array as A
arr = A.array('i',[1,2,3,4,5])
print("Array elements: ",arr)
print("Length of array:",len(arr))
Array elements: array('i', [1, 2, 3, 4, 5])
Length of array: 5
Finding the Length of a Python NumPy ArrayAs we all know, we can create an array
using import numpy as np
arr = np.arange(5)
len_arr = len(arr)
print("Array elements: ",arr)
print("Length of NumPy array:",len_arr)
Output: Array elements: [0 1 2 3 4] Length of NumPy array: 5 ConclusionBy this we have come to the end of this topic. Feel free to comment below, in case you come across any question. Till then, Happy Learning! References
Python has no built-in array data type. But you can create an array using a third-party library like Numpy. To clarify, by array, you probably mean a list in Python. Then, to find the size of the list, use the len() method. To find a length of an array in Python, use the len() method. The len() is a built-in Python method that takes an array as an argument and returns the number of elements in the array. The len() function returns the size of an array. size = len(arr) The len() method takes a required parameter, an array, or a list. # app.py
numbers = [11, 21, 19, 18, 46]
print("The size of an array is: ", len(numbers))OutputThe size of an array is: 5 The size of an array is always one more than the highest array index. For example, the index of the last element of the array is 4; the size of an array is 5. Always +1 of the last index of the element. What the len() function is doing behind the scenes is that it is calling the list.__len__(), and what len() does is it takes the object and tries to call the objects __len__() method. In short, the len() function works only on objects with a __len__() method. If you have a custom object with the __len__() method, you can call len(). Python size of an arrayTo find the size of an array, use the numpy size property. The numpy array has size and shape attributes, but the size and shape attributes are not quite the same. The size is a built-in attribute that returns the size of the array. # app.py
import numpy as np
arr = np.array([[1, 2], [3, 4], [5, 6]])
print("The size of a numpy array is: ", arr.size)
OutputThe size of a numpy array is: 6 In the above code, we get the number of elements in the array with the numpy.size property. The size property works great with one-dimensional arrays. It does not consider the multi-dimensional arrays; it only gives us the number of elements in an array. The shape is a built-in attribute that returns the shape of the array. It counts the number of elements of the array and then returns it. # app.py
import numpy as np
arr = np.array([[1, 2], [3, 4], [5, 6]])
print("The shape of a numpy array is: ", arr.shape)
OutputThe shape of an numpy array is: (3, 2) It returns the shape of the array. numpy array lengthTo find the numpy array length in Python, use the ndarray.size property. The np.ndarray.size attribute returns several elements in the array. The numpy.shape property returns a tuple in the form of (a, b), where a is the number of rows in the array and b is the number of columns in the array. # app.py import numpy as np np_arr = np.arange(3) print(np_arr) print(np_arr.shape) Output[0 1 2] (3,) The shape (= length of each dimension) of numpy.ndarray can be accepted as a tuple with attribute shape. In our case, an array is a one-dimensional array, and that’s why it returns a tuple with one element instead of an integer value. numpy size of 2d arrayTo get the length of a 2D array in Python numpy, use the array.size attribute. The array.size attribute returns the number of elements in the array. # app.py import numpy as np np_arr = np.array([[11, 21], [31, 41]]) print(np_arr) print(np_arr.shape) Output[[11 21] [31 41]] (2, 2) You can see that it is equivalent to np.prod(a.shape), i.e., the product of the array’s dimensions. ConclusionPython, unlike other programming languages like JavaScript or PHP, does not support normal “length()” or “size()” functions to get the size of an array. For example, Instead of “array.length()“, use the len() function, which takes the array itself as a parameter and returns its size. That’s it for this article. See alsoPython list length Python string length Python array contains Python array insert How do you find the LEN of an array in Python?Use the len() method to return the length of an array (the number of elements in an array). How do I print the size of an array?ALGORITHM:. STEP 1: START.. STEP 2: INITIALIZE arr[] = {1, 2, 3, 4, 5}. STEP 3: length= sizeof(arr)/sizeof(arr[0]). STEP 4: PRINT "Number of elements present in given array:" by assigning length.. STEP 5: RETURN 0.. STEP 6: END.. What is Len in array?Returns the length of a given array. array.len( ) Can we use Len for NumPy array?You can use the len() method for NumPy arrays, but NumPy also has the built-in typecode . size that you can use to calculate length. Both outputs return 8, the number of elements in the array. |
