isalpha and isdigit do not work correctly with a subscripted input character

[kenglander53]

Type: Bug

Behaviour

isdigit and isalpha return True incorrectly

Steps to reproduce:

EXAMPLE CODE:

string = "dblcount 12"
items = string.split (" ")
element = items [0]
print (element [0])
if element [0].isalpha:
print ("isalpha is true")
else:
print ("isalpha is false")

if element [0].isdigit:
print ("isdigit is true")
else:
print ("isdigit is false")

element = items [1]
print (element [0])
if element [0].isalpha:
print ("isalpha is true")
else:
print ("isalpha is false")

if element [0].isdigit:
print ("isdigit is true")
else:
print ("isdigit is false")

OUTPUT:

d
isalpha is true
isdigit is true
1
isalpha is true
isdigit is true

Extension version: 2025.16.0
VS Code version: Code 1.105.1 (7d842fb85a0275a4a8e4d7e040d2625abbf7f084, 2025-10-14T22:33:36.618Z)
OS version: Windows_NT x64 10.0.26100
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.13.5
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): System
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

Installed Extensions

Extension Name	Extension Id	Version
debugpy	ms-	2025.14.1
js-debug	ms-	1.105.0
js-debug-companion	ms-	1.1.3
python	ms-	2025.16.0
vscode-js-profile-table	ms-	1.0.10
vscode-pylance	ms-	2025.8.3
vscode-python-envs	ms-	1.10.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) 7 150U (12 x 2611)
GPU Status	2d_canvas: enabled direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off trees_in_viz: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	15.69GB (2.85GB free)
Process Argv	--crash-reporter-id 8fe53d84-2b89-40ee-b241-4fd1371cb725
Screen Reader	no
VM	0%

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2a0ce269:31405347

[eleanorjboyd]

Hi! Could you elaborate a bit more on the problem you are facing? A screenshot or recording could help me understand how exactly you are seeing this behavior in terms of its correlation to the editor. Thanks

[kenglander53]

I do not think it has anything to do with the editor. It is just that I am using the python extension and it is not clear to me how to properly report the issue Anyway, to your question - if you execute the code sample I included, you will see that it does not behave correctly. Yahoo Mail: Search, Organize, Conquer On Thu, Oct 23, 2025 at 10:50 AM, Eleanor ***@***.***> wrote: eleanorjboyd left a comment (microsoft/vscode-python#25543) Hi! Could you elaborate a bit more on the problem you are facing? A screenshot or recording could help me understand how exactly you are seeing this behavior in terms of its correlation to the editor. Thanks — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread.Message ID: ***@***.***>

[eleanorjboyd]

Hi! Tried this and got the following:

d
isalpha is true
isdigit is false
1
isalpha is false
isdigit is true

if you can try this in your terminal without vscode and see how that goes- we should show the same experience as run from your terminal.

[kenglander53]

This is directly from the command line. I suppose this means I need to reinstall python??? I got my version of python from python.org. At the time, I downloaded 3.13.5, which is what it shows when I simply type python at the prompt. [cid:b2d649a9-a77d-4aba-9cf4-04edbca12fa0]

…

________________________________ From: Eleanor Boyd ***@***.***> Sent: Thursday, October 23, 2025 1:43 PM To: microsoft/vscode-python ***@***.***> Cc: kenglander53 ***@***.***>; Author ***@***.***> Subject: Re: [microsoft/vscode-python] isalpha and isdigit do not work correctly with a subscripted input character (Issue #25543) [https://avatars.githubusercontent.com/u/26030610?s=20&v=4]eleanorjboyd left a comment (microsoft/vscode-python#25543)<#25543 (comment)> Hi! Tried this and got the following: d isalpha is true isdigit is false 1 isalpha is false isdigit is true if you can try this in your terminal without vscode and see how that goes- we should show the same experience as run from your terminal. — Reply to this email directly, view it on GitHub<#25543 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BYU6CHC5PHXNPCKKGC2CSC33ZEOVNAVCNFSM6AAAAACKABXT4SVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTIMZYGU4DCMRTGE>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[eleanorjboyd]

Hm not sure but maybe a good thing to try? Sorry I can't help more as it doesn't seem to be an editor issue

[kenglander53]

Hi again - just wanted to send you a "post mortem" note. I finally figured out my problem today and I suspect it is something you just fixed in the code snippet I sent without giving it a moment's thought. I left out the parenthesis after the treatments isdigit and isalpha. I have to admit, it is a puzzle to me why python does not flag this, but I guess it is not something easy to catch!

[eleanorjboyd]

Thank you for the update and agreed that should be flagged - wonder if a different linter like ruff would catch it