Reading JSON Data

A list of records is a table waiting to happen.

Records in, table out

JSON from an API is usually a list of objects, and each object is a row. DataFrame takes that shape directly.

import pandas as pd, json

raw = '[{"name": "Ada", "score": 92}, {"name": "Grace", "score": 88}]'
df = pd.DataFrame(json.loads(raw))
print(list(df.columns))
print(df.shape)

Missing keys become missing values

A record without a key does not break the table. That column simply has a gap on that row, which is the honest result.

import pandas as pd

rows = [{"name": "Ada", "score": 92}, {"name": "Alan"}]
df = pd.DataFrame(rows)
print(df["score"].isna().sum())

Exercise

Try It Yourself

Write from_records(rows) that turns a list of dictionaries into a table and returns its column names, sorted.

import pandas as pd

def from_records(rows):
    # Build a table, return sorted column names.
    return []

print(from_records([{"name": "Ada", "score": 92}]))

Press Run to see output

Check Your Understanding

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