Reading CSV files with read_csv in Pandas - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the read_csv function in pandas?

The read_csv function is used to load data from a CSV file into a pandas DataFrame, making it easy to analyze and manipulate the data in Python.

beginner

How do you specify a different delimiter in read_csv if your file is not comma-separated?

You can use the sep parameter to specify a different delimiter. For example, pd.read_csv('file.csv', sep=';') reads a semicolon-separated file.

beginner

What does the header=None argument do in read_csv?

It tells pandas that the CSV file has no header row, so pandas will assign default column names as numbers starting from 0.

intermediate

How can you read only specific columns from a CSV file using read_csv?

Use the usecols parameter with a list of column names or indices you want to load. For example, pd.read_csv('file.csv', usecols=['Name', 'Age']).

beginner

What happens if you use read_csv on a file path that does not exist?

Pandas will raise a FileNotFoundError, indicating that the file path is invalid or the file does not exist.

Which pandas function is used to load data from a CSV file?

A read_csv

B load_csv

C open_csv

D import_csv

The correct function to read CSV files in pandas is read_csv.

How do you tell read_csv that your CSV file has no header row?

A no_header=True

B header=0

C header=None

D skip_header=True

Using header=None tells pandas the file has no header row.

If your CSV file uses tabs instead of commas, which parameter should you change in read_csv?

A delimiter='\t'

B delimiter='tab'

C separator='tab'

D sep='\t'

The sep parameter specifies the delimiter. For tabs, use sep='\t'.

How can you load only the columns 'Name' and 'Age' from a CSV file?

A select=['Name', 'Age']

B usecols=['Name', 'Age']

C columns=['Name', 'Age']

D cols=['Name', 'Age']

The usecols parameter lets you specify which columns to load.

What error occurs if the CSV file path is wrong when using read_csv?

A FileNotFoundError

B ValueError

C TypeError

D KeyError

A FileNotFoundError is raised if the file path does not exist.

Explain how to use pandas read_csv to load a CSV file that uses semicolons as separators and has no header row.

Think about how to tell pandas about the separator and header.

Describe how you would read only specific columns from a CSV file using pandas.

Focus on the parameter that controls which columns to load.