large-data
Writing large Pandas Dataframes to CSV file in chunks
Solution: header = True for chunk in chunks: chunk.to_csv(os.path.join(folder, new_folder, “new_file_” + filename), header=header, cols=[[‘TIME’,’STUFF’]], mode=”a”) header = False Notes: The mode=”a” tells pandas to append. We only write a column header on the first chunk.
How to efficiently write large files to disk on background thread (Swift)
Performance depends wether or not the data fits in RAM. If it does, then you should use NSData writeToURL with the atomically feature turned on, which is what you’re doing. Apple’s notes about this being dangerous when “writing to a public directory” are completely irrelevant on iOS because there are no public directories. That section …
Red Black Tree versus B Tree
A red/black tree is more or less equivalent to a 2-3-4 tree, which is just a type of B-tree. The worst-case performance is identical, provided you do a binary search of the B-tree node values. The obvious disadvantage of a B-tree is wasted space, but depending on the language/memory allocator used, you may find that …
Is there any JSON viewer to open large json files (windows)? [closed]
You can try Sublime. Its quite good in handling large files:
Parallel.ForEach can cause a “Out Of Memory” exception if working with a enumerable with a large object
The default options for Parallel.ForEach only work well when the task is CPU-bound and scales linearly. When the task is CPU-bound, everything works perfectly. If you have a quad-core and no other processes running, then Parallel.ForEach uses all four processors. If you have a quad-core and some other process on your computer is using one …
Append lines to a file
Have you tried using the write function? line=”blah text blah blah etc etc” write(line,file=”myfile.txt”,append=TRUE)
Shared memory in multiprocessing
Because this is still a very high result on google and no one else has mentioned it yet, I thought I would mention the new possibility of ‘true’ shared memory which was introduced in python version 3.8.0: https://docs.python.org/3/library/multiprocessing.shared_memory.html I have here included a small contrived example (tested on linux) where numpy arrays are used, which …
What causes a Python segmentation fault?
This happens when a python extension (written in C) tries to access a memory beyond reach. You can trace it in following ways. Add sys.settrace at the very first line of the code. Use gdb as described by Mark in this answer.. At the command prompt gdb python (gdb) run /path/to/script.py ## wait for segfault …