Comma-separated values (CSV) is one of the oldest file formats, introduced long before the World Wide Web even existed. However, it is now becoming deprecated as other advanced formats such as JSON and XML are gaining popularity. As the name suggests, data values are separated by commas. The preinstalled csv package and the pandas package contain classes to read and write data in CSV format. The following CSV example defines a population table with two countries:

Country,Time,Sex,Age,Value
United Kingdom,1950,Male,0-4,2238.735
United States of America,1950,Male,0-4,8812.309