why only first character in array?

Question

Hi

this code puts only the first character in the third element of the array. How come and how to solve this?

Thanks. V.

import numpy as np
arr = np.array(["","",""])
arr[2]="abcde"
print(arr[2]) # show only 'a'

Amit Mohanty · Answer

The issue with this code is that the third element of the array is a string of characters and by assigning it to the third element of a numpy array it is implicitly converted to a numpy string scalar. A numpy string scalar is a fixed-size array of characters and when you index it with an integer it returns the character at that position. Therefore when you access arr[2]  which contains a numpy string scalar with the value abcde it returns only the first character 'a'. To solve this issue you can set the dtype of the numpy array explicitly to object  which will allow it to store arbitrary Python objects including strings. Here is an example: import numpy as np arr = np.empty(3 dtype=object) # create empty array with dtype=object arr[2] = abcde # assign string to third element print(arr[2]) # prints 'abcde'

Tuhin Paul · Answer

The code you provided creates a NumPy array of three empty strings and assigns the string abcde to the third element of the array. When you print arr[2] it should output the entire string abcde. import numpy as np arr = np.array([  ]) arr[2] = abcde print(arr[2]) # Output: abcde

Valerie Meunier · Answer

Thanks for replying. You said it's hard to know the exact issue without seeing the code but i gave it: here is it entirely no more no less: import numpy as np arr = np.array([]) arr[2]=abcde print(arr[2]) # show only 'a' You can see that this array has 3 (empty) elements and that the third element gets value abcde. So i don't understand why you make assumptions about that. I ran it into Visual Studio 2022. So why only the first character?

Rajkiran Swain · Answer

The reason why only the first character in an array is being displayed might be due to how the code is accessing and displaying the elements in the array. Without seeing the actual code it's hard to determine the exact cause of the issue but one possibility is that the code is only retrieving the first element of the array and displaying it instead of iterating over each element in the array and displaying them all. Another possibility is that the array contains only one element which is the character 'a' so when the code tries to display the contents of the array it only shows the single element. In any case it's important to thoroughly review the code and the data being used to ensure that all elements in the array are being accessed and displayed correctly.