A collection of challenges that have been either removed from or not (yet) added to the main lesson.
Looping Over DataFrame
(Please refer to lesson
datafolder contains 25 years of data from surveys, starting from 1977. We can extract data corresponding to each year in this DataFrame to individual CSV files, by using a
import pandas as pd # Load the data into a DataFrame surveys_df = pd.read_csv('data/surveys.csv') # Loop through a sequence of years and export selected data start_year = 1977 end_year = 2002 for year in range(start_year, end_year+1): # Select data for the year surveys_year = surveys_df[surveys_df.year == year] # Write the new DataFrame to a CSV file filename = 'data/surveys' + str(year) + '.csv' surveys_year.to_csv(filename)
What happens if there is no data for a year in a sequence? For example, imagine we used
We get the expected files for all years between 1977 and 2002, plus an empty
data/surveys1976.csvfile with only the headers.