Creating DataFrame from list of dictionaries in Pandas - Quick Revision & Summary

Recall & Review

beginner

What is a DataFrame in pandas?

A DataFrame is a table-like data structure in pandas that stores data in rows and columns, similar to a spreadsheet or SQL table.

beginner

How do you create a DataFrame from a list of dictionaries in pandas?

Use the pandas function pd.DataFrame() and pass the list of dictionaries as the argument. Each dictionary becomes a row, and keys become column names.

intermediate

What happens if dictionaries in the list have different keys when creating a DataFrame?

pandas fills missing values with NaN for keys that are not present in some dictionaries, so the DataFrame columns include all keys from all dictionaries.

beginner

Example: Create a DataFrame from this list of dictionaries:<br>[{'name': 'Alice', 'age': 25}, {'name': 'Bob', 'age': 30}]

Code:<br><code>import pandas as pd
people = [{'name': 'Alice', 'age': 25}, {'name': 'Bob', 'age': 30}]
df = pd.DataFrame(people)
print(df)</code><br>Output:<br><code>   name  age
0  Alice   25
1    Bob   30</code>

beginner

Why is creating a DataFrame from a list of dictionaries useful in real life?

It lets you easily convert structured data from sources like JSON files, APIs, or user input into a table format for analysis and visualization.

What does each dictionary in a list represent when creating a DataFrame from it?

A A row in the DataFrame

B A column in the DataFrame

C A cell in the DataFrame

D A DataFrame index

Each dictionary corresponds to one row, with keys as column names.

If some dictionaries lack certain keys, what does pandas put in those DataFrame cells?

A Zero

B NaN (missing value)

C Raises an error

D Empty string

pandas uses NaN to represent missing values in the DataFrame.

Which pandas function creates a DataFrame from a list of dictionaries?

A pd.Series()

B pd.read_csv()

C pd.DataFrame()

D pd.concat()

pd.DataFrame() is used to create DataFrames from various data structures including lists of dictionaries.

What type of data structure is a DataFrame similar to?

A Table or spreadsheet

B List

C Dictionary

D Set

A DataFrame is like a table with rows and columns.

Which of these is a valid way to create a DataFrame from a list of dictionaries named 'data'?

A pd.read_json(data)

B pd.Series(data)

C pd.DataFrame.from_dict(data)

D pd.DataFrame(data)

pd.DataFrame(data) directly converts a list of dictionaries into a DataFrame.

Explain how to create a pandas DataFrame from a list of dictionaries and what happens if some dictionaries have missing keys.

Think about rows, columns, and missing data handling.

Describe a real-life situation where creating a DataFrame from a list of dictionaries would be helpful.

Consider where you get data in dictionary form.