Boolean filtering in Python

A boolean Series selects rows; combine conditions with & and |, in brackets.

import pandas as pd

frame = pd.DataFrame({
    "lang": ["python", "rust", "sql", "css"],
    "tpm": [104, 98, 88, 79],
    "stars": [3, 3, 2, 1],
})

print(frame[(frame["tpm"] > 85) & (frame["stars"] >= 2)])
print(frame[frame["lang"].isin(["rust", "sql"])])
print(frame.query("tpm > 90 and stars == 3"))
print(frame[~frame["lang"].str.startswith("c")].shape)

How it works

and does not work on Series — use & with parentheses.
isin replaces a chain of equality checks.
query reads better when the expression gets long.

Keywords and builtins used here

as
print

The run, in numbers

Lines: 12
Characters to type: 347
Tokens: 151
Three-star pace: 105 tpm

At the three-star pace of 105 tokens a minute, this run takes about 86 seconds.

Type this snippet

Step 3 of 4 in Selecting rows, step 7 of 26 in pandas.

← Previous Next →