Python Program to Retrieve International Database Population Estimates from the Census Data API International Database

c_country_pop.py

# 
# Name:     c_country_pop.py
# Date:     November 15, 2022
# Author:   Randy Runtsch
#
# Description:
#
# Get the mid-year population estimates for a country for the specified year.
# Write the data to a CSV file.



import requests

class c_country_pop:
  
    def __init__(self, out_file_nm, country_code, year, sex_code, write_type, api_key):

        # Set the base URL.
        self.base_url = 'https://api.census.gov/data/timeseries/idb/1year?get=NAME,AGE,POP'

        # Set the parameter variables for the API request.
        self.out_file_nm = out_file_nm
        self.country_code = country_code
        self.year = year
        self.sex_code = sex_code
        self.write_type = write_type
        self.api_key = api_key

        data_in = self.get_data()

        self.write_data_to_csv(data_in)

    def get_data(self):

        # Build the full URL. Then, request the data through the Census Data API. 

        # Create full URL and retrieve data structure in JSON format by calling API with get() function.
        full_url = self.base_url + '&GENC=' + self.country_code + '&YR=' + str(self.year) + '&SEX=' + str(self.sex_code) + '&key=' + self.api_key

        data_in_structure = requests.get(full_url)

        # Convert data content from binary to string.
        data_in = data_in_structure.content.decode('utf-8')

        return data_in

    def write_data_to_csv(self, data_in):


        # Convert the data from the nonstandard JSON format to CSV records. Write
        # each record to the specified output file.

        with open(self.out_file_nm, mode = self.write_type, newline = '') as data_file:
 
            rec_no = 0
            

            for record_in in data_in.splitlines():

                rec_no = rec_no + 1

                # Pass from the loop for one iteration if this is the header (first) record
                # and the write type is append ('a').
                if rec_no == 1 and self.write_type == 'a':

                    continue

                # Strip leading and trailing brackets ([ and ]) and trailing commas from record.
                record_out = record_in.lstrip('[[')
                record_out = record_out.lstrip('[')
                record_out = record_out.rstrip('],')
                record_out = record_out.rstrip(']]')

                # Add a new line to the record out
                record_out = record_out + '\n'

                #Write the CSV record to the output file.
                data_file.write(record_out)

        data_file.close()

get_population_estimates.py

# 
# Name:     get_population_estimates.py
# Date:     November 15, 2022
# Author:   Randy Runtsch
#
# Description:
#
# Use the c_population_estimates class to obtain the population
# of countries by year, gender, and age.

from c_country_pop import c_country_pop

# 
# Call the c_population_estimates constructor with these parameters:
#
# - Folder and JSON file name where debt data will be written.
# - Two-character country code.
# - Year for population estimate.
# - "w" to write records to a new file, or "a" to append records to an existing file.
# - Census data API key.
#

c_country_pop('c:/population_data/pop_2022.csv', 'CN', 2022, 1, 'w', 'YOUR_KEY_GOES_HERE')
c_country_pop('c:/population_data/pop_2022.csv', 'CN', 2022, 2, 'a', 'YOUR_KEY_GOES_HERE')

c_country_pop('c:/population_data/pop_2022.csv', 'JP', 2022, 1, 'a', 'YOUR_KEY_GOES_HERE')
c_country_pop('c:/population_data/pop_2022.csv', 'JP', 2022, 2, 'a', 'YOUR_KEY_GOES_HERE')

c_country_pop('c:/population_data/pop_2022.csv', 'NO', 2022, 1, 'a', 'YOUR_KEY_GOES_HERE')
c_country_pop('c:/population_data/pop_2022.csv', 'NO', 2022, 2, 'a', 'YOUR_KEY_GOES_HERE')

c_country_pop('c:/population_data/pop_2022.csv', 'US', 2022, 1, 'a', 'YOUR_KEY_GOES_HERE')
c_country_pop('c:/population_data/pop_2022.csv', 'US', 2022, 2, 'a', 'YOUR_KEY_GOES_HERE')