python_shines.py

import gzip
from collections import defaultdict
import numpy as np
import pandas as pd
from tqdm import tqdm

# calculate the number of lines with zcat commits.csv.gz | wc -l
size = 485226041
hashes = np.zeros(size, dtype="S20")
authors = np.zeros(size, dtype="u4")
committers = np.zeros(size, dtype="u4")

# read line by line and don't use pd.read_csv for less memory
with gzip.open("commits.csv.gz") as fin:
    for i, line in enumerate(tqdm(fin, total=size)):
        parts = line.decode().split(",")
        hashes[i] = np.frombuffer(bytes.fromhex(parts[1][1:-1]), dtype="S20")
        authors[i] = int(parts[2])
        committers[i] = int(parts[3])
# sort by commit hash
order = np.argsort(hashes)
hashes = hashes[order]
authors = authors[order]
committers = committers[order]
# load the CSV from BigQuery
# actually, I had to merge 6 separate CSV chunks here due to
# BigQuery output limitations on Google Drive (less than 1GB)
bq_df = pd.read_csv("bigquery-results.csv.gz")
# a dict with the commit hashes will consume too much memory
# so we get away with np.searchsorted
people = defaultdict(set)
acc_membership = defaultdict(set)
for author, committer, commit, acc in tqdm(zip(
        bq_df["name"].values, bq_df["name_1"].values,
        bq_df["commit"].values, bq_df["f0_"].values),
        total=len(bq_df)):
    h = bytes.fromhex(commit)
    index = np.searchsorted(commits_to_find, h)
    if hashes[index] != h:
        continue
    # check isinstance(author, str) to avoid inserting NANs
    if isinstance(author, str):
        people[(author_id := authors[index])].add(author)
    if isinstance(committer, str):
        people[(committer_id := committers[index])].add(committer)
    acc_membership[acc].add(author_id)
    acc_membership[acc].add(committer_id)

Can you tell me what the commits_to_find and found_indexes objects are supposed to be? I am trying to learn more through examples like this and I really appreciate you sharing this openly online, but I can't seem to figure out those two things and I can't get to the point of playing around with string matching algorithms.

Hi @jmkehayias

commits_to_find is np.array(dtype="S20") - 20-byte hashes. I think that I missed a rename from hashes. And the line index = found_indexes[index] should be removed. Sorry for the raw code.

I fixed it.