why only first character in array?

Valerie Meunier

3y1.1kPython

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'

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Amit Mohanty3y ago
Accepted 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'
```
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Tuhin Paul3y ago
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
```
+1
Valerie Meunier3y ago
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?
0
Rajkiran Swain3y ago
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.
0