Snippet library

Copy-ready, tested snippets for Python, Flask, JavaScript, SQL, HTML, CSS and Bash. Open any of them in the playground.

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2 snippets

python

Group items by a key

Turn a flat list into a dict of lists with collections.defaultdict.

from collections import defaultdict

orders = [
    {"customer": "ada", "total": 30},
    {"customer": "linus", "total": 12},

beginner #collections#dict#data

python

Read and write CSV files

Read rows as dicts and write a filtered copy with csv.DictWriter.

import csv
import io

source = io.StringIO("name,score\nada,91\nlinus,78\ngrace,88\n")   # use open("in.csv") for a file
rows = [row for row in csv.DictReader(source) if int(row["score"]) >= 80]

beginner #csv#files#data

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Snippet library

Group items by a key

Read and write CSV files