如何在python中编写for循环以仅从csv文件中提取唯一值以加载到我的API脚本中？

Question

I am working on fetching weather API data from https://www.worldweatheronline.com/developer/

My script in python:

from wwo_hist import retrieve_hist_data
frequency=12
start_date = '11-JAN-2018'
end_date = '11-JAN-2019'
api_key = 'MYKEY'
location_list = [ "Lancaster","Canton"]

hist_weather_data = retrieve_hist_data(api_key,
                                location_list,
                                start_date,
                                end_date,
                                frequency,
                                location_label = False,
                                export_csv = True,
                                store_df = True)

While this does give me my output because I manually type in my location_list, I want it to read through my csv dataframes column for every unique city name.

My csv dataframe reprex is as follows(used R's unique function):

unique(MyData$City)
   [1] Lancaster                Canton                   Edison                  
   [4] East Walpole             Dayton                   Fort Wainwright         
   [7] Crystal                  Medford                  Spring Valley           
  [10] Hillsdale                Newyork                  Butte                   
  [13] Alameda                  Monroe                   Astoria                 
  [16] Austin                   Cortlandt Manor          Central Square          
  [19] Redding                  Morgantown               Tyngsboro               
  [22] Peabody                  Wenonah                  Milford                 
  [25] Groton                   Springfield              Palermo                 
  [28] Helotes                  Conroe                   Somerset                
  [31] Clifton Park             Aberdeen                 Palm Springs            
  [34] Gilbert                  Hopkinton                San Diego               
  [37] Detroit                  Carrollton               Calabasas               
  [40] Parker                   Pleasant Hill            San Jose

How can i automate it to pick up the unique city names and use it for location_list instead of manually entering each city name?

Answer 1

You could do it like this, substituting my_csv.csv with your csv file, and 'city' with the name of the column in the csv file where your city data is.

import csv
my_cities = []
with open('my_csv.csv', newline='') as csvfile:
    my_data = csv.reader(csvfile, delimiter=',')
    for index, row in enumerate(my_data):
        if index == 0:
            my_column_index = row.index('city')
        if index != 0 and len(row) > 0:
            my_cities.append(row[my_column_index])
location_list = list(set(my_cities))

Alternatively, if you're willing to install Pandas:

import pandas as pd
my_cities = pd.read_csv('my_csv.csv')['city'].unique()
location_list = list(my_cities)

Answer 2

Using pandas

>>> df = pandas.DataFrame([{'City': 'Foo'}, {'City': 'Bar'}, {'City': 'Foo'}])
>>> df['City'].unique()
array(['Foo', 'Bar'], dtype=object)