Dictionary-based CSV handling in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What Python module is commonly used for reading and writing CSV files using dictionaries?

The csv module provides DictReader and DictWriter classes to handle CSV files as dictionaries.

beginner

How does csv.DictReader represent each row of a CSV file?

csv.DictReader reads each row as a dictionary where keys are column headers and values are the row's data.

beginner

What method do you use to write a dictionary row to a CSV file using csv.DictWriter?

Use the writerow() method of csv.DictWriter to write a single dictionary as a CSV row.

intermediate

Why is using dictionary-based CSV handling helpful compared to normal CSV reading?

It allows you to access data by column names instead of index positions, making code easier to read and less error-prone.

beginner

What must you do before writing rows with csv.DictWriter to ensure the CSV file has headers?

Call the writeheader() method once to write the column headers before writing any rows.

Which class reads CSV rows as dictionaries with column headers as keys?

A csv.DictReader

B csv.reader

C csv.DictWriter

D csv.writer

csv.DictReader reads CSV rows as dictionaries using headers as keys.

What method writes the header row when using csv.DictWriter?

A writeheader()

B writerow()

C write()

D writeheaders()

The writeheader() method writes the CSV header row.

If you want to write a dictionary {'name': 'Anna', 'age': 30} as a CSV row, which method do you use?

A readrow()

B writerow()

C writeheader()

D write()

writerow() writes a single dictionary as a CSV row.

What is the main advantage of using dictionary-based CSV handling?

A Compresses CSV files

B Faster file reading

C Automatically sorts data

D Access data by column names, improving readability

Using dictionaries lets you access data by column names, making code clearer.

Which of these is NOT a feature of csv.DictReader?

A Reads rows as dictionaries

B Uses column headers as keys

C Writes CSV files

D Handles missing fields gracefully

csv.DictReader reads CSV files; it does not write them.

Explain how to read a CSV file using dictionary-based handling in Python.

Think about how to open a file and use DictReader to get rows as dictionaries.

Describe the steps to write a list of dictionaries to a CSV file using csv.DictWriter.

Remember to write headers before rows.