How can I get the first n elements of an iterator (generator) in the simplest way? Is there something simpler than, e. g. I can’t think of a nicer way, but maybe there is? Maybe a functional form? Answer Use itertools.islice(): This will yield the next 3 elements from it, then stop.
Tag: python
A recursive function to sort a list of ints
I want to define a recursive function can sort any list of ints: Calling this function on a list [3, 1, 2,4,7,5,6,9,8] should give me: But I get: Please help me to fix the problem, actual code would be appreciated. Thanks! Answer The quick sort is recursive and easy to implement in Python: will give:
Javascript to Django views.py?
This may sound simple, but how do I send the data from a Javascript array in my index.html template to my views.py? When the user clicks a “Recommend” button, my code calls a function that accesses my database and prints a name on the template. I have an array of checkbox values in Javascript that…
Python imports relative path
I’ve got a project where I would like to use some python classes located in other directories. Example structure: The absolute path varies, because this project is run on different machines. When my python file with MySampleClass located in /mydir is executed, how do I import OtherClassRoot located in /…
Pandas Replace NaN with blank/empty string
I have a Pandas Dataframe as shown below: I want to remove the NaN values with an empty string so that it looks like so: Answer This might help. It will replace all NaNs with an empty string.
Is there a faster version of numpy.random.shuffle?
I’m using numpy.random.shuffle in order to compute a statistic on randomized columns of a 2D array. The Python code is as follows: The speed I get is something like this: 1 loops, best of 3: 391 ms per loop I tried to Cythonize this function but I wasn’t sure how to replace the call to np.random.s…
pygame.error: video system not initialized
I am getting this error whenever I attempt to execute my pygame code: pygame.error: video system not initialized Answer You haven’t called pygame.init() anywhere. See the basic Intro tutorial, or the specific Import and Initialize tutorial, which explains: Before you can do much with pygame, you will ne…
python urllib2 and unicode
I would like to collect information from the results given by a search engine. But I can only write text instead of unicode in the query part. give this error Answer Encode the Unicode data to UTF-8, then URL-encode: Demo: Using urllib.urlencode() to build the parameters is easier, but you can also just escap…
How to get PID by process name?
Is there any way I can get the PID by process name in Python? For example I need to get 3110 by chrome. Answer You can get the pid of processes by name using pidof through subprocess.check_output: check_output([“pidof”,name]) will run the command as “pidof process_name”, If the return …
Align matplotlib scatter marker left and or right
I am using the matplotlib scatterplot function to create the appearance of handles on vertical lines to delineate certain parts of a graph. However, in order to make them look correct, I need to be able to align the scatter plot marker to the left (for the left line / delineator) and / or right (for the right…