Is there any way to copy a particular column from excel sheet (say sheet_1) to the other column which is in sheet_2? Using Python

Question

Please find the code below:

import pandas as pd
import csv

# Reading the csv file 
df_new = pd.read_csv('source.csv') 

# saving xlsx file 
GFG = pd.ExcelWriter('source.xlsx') 
df_new.to_excel(GFG, index = False) 

GFG.save() 

# read excel
xl = pd.ExcelFile("source.xlsx")
df = xl.parse("Sheet1")

# get the column you want to copy
column = df["Marks"]

# paste it in the new excel file
with pd.ExcelWriter('Target_excel.xlsx', mode='A') as writer:
    column.to_excel(writer, sheet_name= "new sheet name", index = False)

writer.close()

In this code, it is replacing the existing contents of the target excel file. I want to update a column in sheet 2 without changing other columns.

Example:

Excel file 1--> column_name = 'Marks'

Marks = 10,20,30

Excel file 2--> there are two columns present in this file

Subject_name = Math, English, Science

Marks = 50, 20, 40

So I want to copy "Marks" column from Excel file 1 and paste it into "Marks" column of Excel file 2(Without changing the data of "Subject" column)

Answer 1

import pandas as pd
import openpyxl as pxl

def get_col_idx(worksheet, col_name):
    return next((i for i, col in enumerate(worksheet.iter_cols(1, worksheet.max_column)) if col[0].value == col_name), -1)

### ----- 0. csv -> xlsx (no change from your code)

df_new = pd.read_csv("source.csv")

GFG = pd.ExcelWriter("source.xlsx")
df_new.to_excel(GFG, index=False)
GFG.save()

### ----- 1. getting data to copy

# open file and get sheet of interest
source_workbook = pxl.load_workbook("source.xlsx")
source_sheet = source_workbook["Sheet1"]

# get "Marks" column index
col_idx = get_col_idx(source_sheet, "Marks")

# get contents in each cell
col_contents = [row[col_idx].value for row in source_sheet.iter_rows(min_row=2)]

### ----- 2. copy contents to target excel file

target_workbook = pxl.load_workbook("Target_excel.xlsx")
target_sheet = target_workbook["new sheet name"]

col_idx = get_col_idx(target_sheet, "Marks")

for i, value in enumerate(col_contents):
    cell = target_sheet.cell(row=i+2, column=col_idx+1)
    cell.value = value

target_workbook.save("Target_excel.xlsx")