(Closed) Python CSV: (Master and Detail) Search and Insert Value From Detail File into Specific Column On Master File

Question

I am new in Python actually ):

I have task regarding Python and CSV where I need to add value into specific column on Master file after getting data from Detail file.

Let see sample Master File, Detail File and Output expected.

Master File:

Detail File:

Output Expected:

I have a few source-code to run it but not complete on this stage.
Let See what I have below:

from csv import DictReader
from collections import defaultdict


loaded = defaultdict(list)
month1=[]
month2=[]
month3=[]


def getdetailpayment(data):
    f=open(data)
    csv_file = csv.DictReader(f, delimiter=",")
    for row in csv_file:
        print(dict(row))
    f.close()

def search_masterfile(data):
    word = input("Search name: ")
    f=open(data)
    my_reader=csv.DictReader(f,delimiter=",")
    for row in my_reader:
        for entry in row:
            if row[entry]==word:
                print(row)
    #insert value into this row on specific column
   
   
    f.close()   
                  
search_masterfile("csv/master.csv")
getdetailpayment("csv/detail.csv")

My plan to playing with dictionary where I assumed I can insert into Master file value and specific column based Detail file record existing. Unfortunately I am very weak of knowledge regarding this scope and I already try to get source-code from google but still not what I wants.

Please help me guys regarding this matter and I prompt thank you very munch on advance.

Asked By: nonothingnull

||

Source

Answer 1

If you want to do this with basic Python you could try the following:

import csv
from datetime import datetime as dt

with open("master.csv", "r") as file:
    reader = csv.DictReader(file)
    fieldnames = reader.fieldnames
    master = {(row["Name"], row["Key No"]): row for row in reader}

def to_month(string):
    return f"Month {dt.strptime(string, '%b-%y').month}"
    
with open("details.csv", "r") as file:
    next(file)
    for name, key, month, amount in csv.reader(file):
        master[name, key][to_month(month)] = amount

with open("result.csv", "w") as file:
    writer = csv.DictWriter(file, fieldnames=fieldnames)
    writer.writeheader()
    writer.writerows(master.values())

The first step reads the master file (here master.csv) into a dictionary master with (Name, Key No) tuples as keys (for the merging). On the way the column names get picked up (fieldenames) for the writing later.
The second step is reading through the details file (here details.csv) and updating the respective values in master. The to_month function transforms the month-strings into the corresponding key (column name).
Then write the result into a new file (here result.csv).

You might have to adjust the filenames.

The result for the given input

master.csv:

Name,Key No,Month 1,Month 2,Month 3
A,1,,,
B,2,,,
C,3,,,
D,4,,,

details.csv:

Name,Key No,Month,Amount
A,1,Feb-22,100
B,2,Jan-22,80
C,3,Feb-22,80
D,4,Jan-22,100
A,1,Jan-22,200
C,3,Jan-22,90

is the following file result.csv:

Name,Key No,Month 1,Month 2,Month 3
A,1,200,100,
B,2,80,,
C,3,90,80,
D,4,100,,

If you have to do stuff like this often you might want to look into the Pandas library.

Answered By: Timus

(Closed) Python CSV: (Master and Detail) Search and Insert Value From Detail File into Specific Column On Master File

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