How do I concatenate two one-dimensional arrays in NumPy? I tried numpy.concatenate: But I get an error: TypeError: only length-1 arrays can be converted to Python scalars Answer Use: The arrays you want to concatenate need to be passed in as a sequence, not as separate arguments. From the NumPy documentation…
Tag: python
In Python argparse, is it possible to have paired –no-something/–something arguments?
I’m writing a program in which I would like to have arguments like this: Is there a way to get argparse to do this for me? Answer v3.9 has added an action class that does this. From the docs (near the end of the action section) The BooleanOptionalAction is available in argparse and adds support for bool…
Memory dump formatted like xxd from gdb
I’m trying to inspect a buffer which contains a binary formatted message, but also contains string data. As an example, I’m using this C code: I’d like to get a hex dump of what’s in buf, of a format similar to xxd (I don’t care if it’s an exact match, what I’m really…
Is python zipfile thread-safe?
In a django project, I need to generate some pdf files for objects in db. Since each file takes a few seconds to generate, I use celery to run tasks asynchronously. Problem is, I need to add each file to a zip archive. I was planning to use the python zipfile module, but different tasks can be run in differen…
How can I force Python’s file.write() to use the same newline format in Windows as in Linux (“rn” vs. “n”)?
I have the simple code: Code runs on windows and gives file size 12 bytes, and linux gives 11 bytes The reason is new line In linux it’s n and for win it is rn But in my code I specify new line as n. The question is how can I make python keep new line as n always, and
How do you get the magnitude of a vector in Numpy?
In keeping with the “There’s only one obvious way to do it”, how do you get the magnitude of a vector (1D array) in Numpy? The above works, but I cannot believe that I must specify such a trivial and core function myself. Answer The function you’re after is numpy.linalg.norm. (I reckon…
Using a dictionary to select function to execute
I am trying to use functional programming to create a dictionary containing a key and a function to execute: Now, I have seen a code used to find the defined functions in a module, and I need to do something like this: So my question is, How do I make a list of all the Exec functions and then assign
How do I raise the same Exception with a custom message in Python?
I have this try block in my code: Strictly speaking, I am actually raising another ValueError, not the ValueError thrown by do_something…(), which is referred to as err in this case. How do I attach a custom message to err? I try the following code but fails due to err, a ValueError instance, not being …
Asynchronous Requests with Python requests
I tried the sample provided within the documentation of the requests library for python. With async.map(rs), I get the response codes, but I want to get the content of each page requested. This, for example, does not work: Answer Note The below answer is not applicable to requests v0.13.0+. The asynchronous f…
How can I check if a string contains ANY letters from the alphabet?
What is best pure Python implementation to check if a string contains ANY letters from the alphabet? Where string_1 would return False for having no letters of the alphabet in it and string_2 would return True for having letter. Answer Regex should be a fast approach: