Hantera kolumner med nästlad data

Omforma data med pandas

Maria Eugenia Inzaugarat

Data Scientist

Repetition

Hur man läser nästlad JSON till en DataFrame med json_normalize().

Nästlad data i kolumner

writers = ["Mary Shelley", "Ernest Hemingway"]
books = ["{'title': 'Frankenstein', 'year': 1818}", 
        "{'title': 'The Old Man and the Sea', 'year': 1951}"]

collection = pd.DataFrame(                                  )

Nästlad data i kolumner

writers = ["Mary Shelley", "Ernest Hemingway"]
books = ["{'title': 'Frankenstein', 'year': 1818}", 
        "{'title': 'The Old Man and the Sea', 'year': 1951}"]

collection = pd.DataFrame(dict(                            ))

Nästlad data i kolumner

writers = ["Mary Shelley", "Ernest Hemingway"]
books = ['{"title": "Frankenstein", "year": "1818"}',
         '{"title": "The Old Man and the Sea", "year":"1951"}']

collection = pd.DataFrame(dict(writers=writers, books=books))

collection

            writers                                               books
0      Mary Shelley             {'title': 'Frankenstein', 'year': 1818}
1  Ernest Hemingway  {'title': 'The Old Man and the Sea', 'year': 1951}

Konvertera nästlad data

import json

books = collection['books']

Konvertera nästlad data

import json

books = collection['books'].apply(          )

Konvertera nästlad data

import json

books = collection['books'].apply(json.loads)

Konvertera nästlad data

import json

books = collection['books'].apply(json.loads).apply(pd.Series)

books

                     title  year
0             Frankenstein  1818
1  The Old Man and the Sea  1951

Slå ihop igen

collection = collection.drop(columns='books')

pd.concat([collection, books], axis=1)

            writers                    title  year
0      Mary Shelley             Frankenstein  1818
1  Ernest Hemingway  The Old Man and the Sea  1951

Exportera nästlad data

import json
books = collection['books'].apply(json.loads)

Exportera nästlad data

import json
books = collection['books'].apply(json.loads).to_list()

books_dump = json.dumps(books)

new_books = pd.read_json(books_dump)

new_books

                     title  year
0             Frankenstein  1818
1  The Old Man and the Sea  1951

Exportera nästlad data

pd.concat([collection['writers'], new_books], axis=1)

            writers                    title  year
0      Mary Shelley             Frankenstein  1818
1  Ernest Hemingway  The Old Man and the Sea  1951

Nu kör vi en övning!

Omforma data med pandas