Replacing data from dataframe with data from another dataframe

Question

I currently have a dataframe and a csv file.

In the csv file, I have about 30 columns, including one column of ZIP codes (eg, "10001", "08983", "85321"). CSV is 3400 rows x 30 columns.

In the dataframe, I have a column of ZIP codes and a matching column of scores:

zipcode  score
99780    2.250000
99801    2.719083
99824    2.721311
99827    2.285714
99835    2.534783
99901    2.501558
[27688 rows x 1 columns]

I want to go to my csv file, look at each ZIP code, match the ZIP code up with the dataframe, and add a new column that notes the score that's stored in the dataframe. I would also be OK with just flat out replacing the ZIP code in the csv file with the score in the dataframe, if that's faster.

The reason why .replace isn't going to work is because I don't want to manually enter all 27688 ZIP codes and say what those should be replaced by.

Any ideas?

EDIT : Here's what a row in the CSV file currently looks like:

Name     Age     DOB     Gender     Hair Color     Eye Color     ZIP
John Doe 22      6-10    Male       Brn            Brn           99780

And here's what I want it to look like:

Name     Age     DOB     Gender     Hair Color     Eye Color     ZIP     Score
John Doe 22      6-10    Male       Brn            Brn           99780   2.250000

I'm also OK with the "Score" column flat-out replacing the ZIP column.

Answer 1

Have you tried loading the csv into a list and then looping through the items in the list.

import csv
sFile = "myfile.csv"
with open(sFile, 'rb') as f:
    reader = csv.reader(f)
    yourList = list(reader)

for item in yourList:
    #search and replace based on each item

You can also try merge from pandas.

Update: Using Merge

Here is an example of using merge:

import pandas as pd

df = pd.DataFrame([[12345,"Atlanta"],[54321,"Orlando"]], columns=['Zip','City'])

df2 = pd.read_csv('Zip.csv')

df3 = pd.merge(df,df2,how="left", )

print (df3)

The result:

     Zip     City     State
0  12345  Atlanda   Georgia
1  54321  Orlando   Florida