CSV with dictionaries in Python

Reading and writing CSV rows as dicts.

import csv
import io

raw = "name,score\nada,95\ngrace,88\nkatherine,92\n"

reader = csv.DictReader(io.StringIO(raw))
rows = list(reader)
top = max(rows, key=lambda r: int(r["score"]))

out = io.StringIO()
writer = csv.DictWriter(out, fieldnames=["name", "score"])
writer.writeheader()
writer.writerows(rows)
text = out.getvalue()

How it works

1. DictReader yields each row keyed by header.
2. max with a key finds the top row.
3. DictWriter writes the header and rows back out.

Keywords and builtins used here

• int
• lambda
• list
• max

The run, in numbers

Lines

14

Characters to type

330

Tokens

101

Three-star pace

105 tpm

At the three-star pace of 105 tokens a minute, this run takes about 58 seconds.

Type this snippet

Step 2 of 5 in Data formats, step 18 of 41 in Domain tools.

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