When we read data from a CSV format file, we have two general choices for the resulting data structure:
- When we use csv.reader(), each row becomes a simple list of column values.
- When we use csv.DictReader, each row becomes a dictionary. By default, the contents of the first row become the keys for the row dictionary. We can also provide a list of values that will be used as the keys.
In both cases, referring to data within the row is awkward because it involves rather complex-looking syntax. When we use a reader, we must use row[0], the semantics of this are completely obscure. When we use a DictReader, we can use row['date'], which is less obscure, but is a lot of typing.
In some real-world spreadsheets, the column names are impossibly long strings. It's hard to work with row['Total of all locations...
