I have an array X and I want to apply a function f to all the rows of X: Now, y should be array([15,30], ‘i’). Which method or slicing magic will implement rows in the most efficient way? Answer NumPy implements the concept of “action over a particular axis”. The general function is nu…
Tag: python
Automatically-generated Python constructor
I have countless Python classes from various projects from SQLAlchemy (and a couple from Pygame as well), and I recently noticed a pattern in many of them: their constructors always went something like this: … whereby the only thing the constructor did was to transfer a set of positional arguments into …
How do I remove all zero elements from a NumPy array?
I have a rank-1 numpy.array of which I want to make a boxplot. However, I want to exclude all values equal to zero in the array. Currently, I solved this by looping the array and copy the value to a new array if not equal to zero. However, as the array consists of 86 000 000 values and I have
Prepend line to beginning of a file
I can do this using a separate file, but how do I append a line to the beginning of a file? This starts writing from the end of the file since the file is opened in append mode. Answer In modes ‘a’ or ‘a+’, any writing is done at the end of the file, even if at the current moment
In Python on Unix, determine if I am using my computer? or idle?
I would like to write a script to do an heavy network upload, in the background. However, I would like it to pause when I am using my computer (either by detecting network activity or keyboard activity or that I am not idle). What is the best way to detect that I am using the computer, on Python on Unix?
Recursive diff of two dictionaries (keys and values)?
So I have a python dictionary, call it d1, and a version of that dictionary at a later point in time, call it d2. I want to find all the changes between d1 and d2. In other words, everything that was added, removed or changed. The tricky bit is that the values can be ints, strings, lists, or dicts, so
Django DateTimeField auto_now_add not working
In one of the model i have set one timestamp field as follows: While in shell i am able to create a obj and save it, however in my application it is raising a exception that created_datetime field cannot be null. Confused where things went wrong!! How to reslove it. Answer You can do something like this
Python: How do I display a timer in a terminal
I’m new to python programming and using ubuntu to do so. In a program I have done I used a delay of 1 minute until it executes the code again. How can I program a timer to be displayed in the terminal based on the value of the delayed time? Thanks in advance… Answer The simplest way is as follows.
Joining pairs of elements of a list [duplicate]
This question already has answers here: How to iterate over a list in chunks (39 answers) Closed 8 months ago. I know that a list can be joined to make one long string as in: Obviously this would output: However, what I am trying to do is simply join the first and second strings in the list, then join the
Generating PDFs from SVG input
I am trying to generate a PDF from a SVG input file with Python in a Django application. I have already found 2 working solutions: cairo+rsvg and imagemagick but they both have one problem: They have some strange dependencies that I do not want to install on a server, for example DBUS and GTK. So I am asking …