使用 WHILE 循环组合多个数据框

Question

Screenshot of results from Updated code from suggestion

'dlist' is a list of provider id that is in a dataframe. I tried to use a while loop for 'dlist', but it only returns the value of the last provider id in the array. In this case it is 1005. I used the append function but it didn't do anything. The additional 74 rows from provider id 1000 are not showing. How do I combine everything so it shows the values of both numbers from dlist, to equal 684 rows?

dlist = ["1000", "1005"]

final_list = pd.DataFrame()

index = 0

while index < len(dlist):
    provider = dlist[index]
    
    # Filter dentist (CHANGEABLE)
    final_list = report_df[(report_df["provider_id"] == provider)]

    # Sort values of the codes
    final_list = final_list.sort_values(['codes','report_month'], ascending=True)

    # Drop 'report_year' column
    final_list = final_list.drop(['report_year'], axis = 1)

    # Change 'report_month' numbers into month name
    final_list = final_list.replace({'report_month': {1: "January",
                                                      2: "February",
                                                      3: "March",
                                                      4: "April",
                                                      5: "May",
                                                      6: "June",
                                                      7: "July",
                                                      8: "August",
                                                      9: "September",
                                                      10: "October",
                                                      11: "November"}})
    final_list.append(final_list)
    index +=1

Missing values

Result of the current code

Answer 1

Could create a list with all the dataframes and then concatenate them. Like before the while loop have a list_of_dfs = [] , and prior to the index+=1 add list_of_dfs.append(final_list) . You probably dont want final_list.append(final_list) . Eventually could do my_df_of_concern = pd.concat(list_of_dfs, index=0) . Seehttps://pandas.pydata.org/docs/reference/api/pandas.concat.html

Answer 2

Your problem is you are modifying the same variable again and again. In your code:

Line 1: while index < len(dlist):
Line 2:    provider = dlist[index]
    
Line 3:    # Filter dentist (CHANGEABLE)
Line 4:    final_list = report_df[(report_df["provider_id"] == provider)] # PROBLEM LINE
Line 5:    # MORE CODE
Line 6:    # MORE CODE
Line 7:    final_list.append(final_list)
Line 8:    index +=1

Since your dlist has ["1000", "1005"] , during the first run, in line 4, final_list has all the rows where provider_id == 1000 . Then you make some modifications to it and then in Line 7, you append it to the same object. So now, final_list is going to have 2 copies of everything because you are doing final_list.append(final_list)

Then you increment index and for the next iteration where provider is now 1005 , you again do Line 4 where by your final_list is going to be overwritten. This means that all your previous values stored in that variable is no longer present only the new values where provider_id == 1005 is present.

Try changing your code like this

while index < len(dlist):
    provider = dlist[index]
    
    # Filter dentist (CHANGEABLE)
    report_list = report_df[(report_df["provider_id"] == provider)]

    # Sort values of the codes
    report_list = report_list.sort_values(['codes','report_month'], ascending=True)

    # Drop 'report_year' column
    report_list = report_list.drop(['report_year'], axis = 1)

    # Change 'report_month' numbers into month name
    report_list = report_list.replace({'report_month': {1: "January",
                                                      2: "February",
                                                      3: "March",
                                                      4: "April",
                                                      5: "May",
                                                      6: "June",
                                                      7: "July",
                                                      8: "August",
                                                      9: "September",
                                                      10: "October",
                                                      11: "November"}})
    final_list.append(report_list)
    index +=1

report_list acts as a temporary variable which holds all the data of a particular provider and then after all your modifications like dropping report_year column, sorting, etc. you append the values to final_list. Now you will have the data across multiple iterations.

Also, instead of doing

while index < len(dlist):
    provider = dlist[index]
    index +=1

you can do this:

for provider in dlist:
    # YOUR CODE where provider will be "1000" for 1st run and "1005" in second run