Develop Reference

Python reading an updated excel file

I’m really stuck on what should be an easy problem.
I have an excel workbook that I’m making an update to 2 Columns for one record for the clean_data sheet. From there, I’m saving and closing the file.
After that, I’m trying to pull in the updated roll up sheet values as a data frame (graphs_rolling) which has formulas utilizing the clean_data sheet.
When I view the data frame, all the values are Nan. I can open the exel file and see the updated values on the graphs_rolling sheet. What can I do to fix the data frame to populate with values?
Code is shown below:
import pandas as pd
import openpyxl
from openpyxl import load_workbook
#Import Data with Correct Rows and Columns for SSM Commercial
book = load_workbook('//CPI Projects//Test//SampleSSM//NewSSM.xlsx')
writer = pd.ExcelWriter('//CPI Projects//Test//SampleSSM//NewSSM.xlsx', engine = 'openpyxl')
writer.book = book
df1 = pd.read_excel('//CPI Projects//Test//SampleSSM//NewSSM.xlsx',sheet_name='clean_data')
df1.loc[df1['ev_id']==20201127, 'commercial_weight'] = 0 df1.loc[df1['ev_id']==20201127, 'commercial'] = 0
book.remove(book['clean_data'])
df1.to_excel(writer, sheet_name = 'clean_data',index=False)
writer.save()
writer.close()
df5 = pd.read_excel('//CPI Projects//Test//SampleSSM//NewSSM.xlsx',sheet_name='graphs_rolling_avg',skiprows=30)
print(df5)

Having Trouble Writing Table to Excel with Python

Hi I am trying to create a table in excel using a dataframe from another excel spreadsheet and writing the table to a new one. I believe my code is correct but the table isn't writing to the new excel spreadsheet. Can someone take a look at my code and tell me what's wrong?
import xlsxwriter
import pandas as pd
import openpyxl as pxl
import xlsxwriter
import numpy as np
from openpyxl import load_workbook
path = '/Users/benlong/Downloads/unemployment.xlsx'
df = pd.read_excel(path)
rows = df.shape[0]
columns = df.shape[1]
wb = xlsxwriter.Workbook('UE2.xlsx')
ws = wb.add_worksheet('Sheet1')
ws.add_table(0,0,rows,columns, {'df': df})
wb.close()

You should convert your dataframe to list . By using df.values.tolist() and use the key data.
In your case , you also should set the header of df and avoid getting a nan value error.
eg:
import xlsxwriter as xlw
# while got NaN/Inf values from ur dataframe , u'll get a value of '#NUM!' instead in saved excel
wb = xlw.Workbook('UE2.xlsx',{'nan_inf_to_errors': True})
ws = wb.add_worksheet('Sheet1')
cell_range = xlw.utility.xl_range(0, 0, rows, columns-1)
header = [{'header': str(di)} for di in df.columns.tolist()]
ws.add_table(cell_range, {'header_row': True,'first_column': False,'columns':header,'data':df.values.tolist()})
wb.close()

Possible duplicate: How to use xlsxwriter .add_table() method with a dataframe?
You can try converting the dataframe to a list of lists and use the data keyword.
ws.add_table(0,0,rows,columns, {'data': df.values.T.tolist()})

Read excel files from a folder, extract a cell from sheet-1 and append values to a new excel sheet

I have around 100 excel files in a folder. I need to extract a cell, say name column D6 from the sheet-1 of the excel files and output the same to a new excel file/sheet. I have a followed a few SO questions but have not been able to find the desired output. This is what my issue is when I run the below program`
TypeError: cannot concatenate a non-NDFrame object
`
import os
import pandas as pd
import xlrd
import xlwt
files = os.listdir(path)
files
all_data = pd.DataFrame()
for file in files:
wb = xlrd.open_workbook(file)
sheet = wb.sheet_by_index(0)
df = sheet.cell_value(5,3)
all_data.append(df,ignore_index=True)
writer = pd.ExcelWriter('output.xlsx', engine='xlsxwriter')
all_data.to_excel(writer,'sheet1')
writer.save()

Your error says that you can only concat a dataframe with another dataframe. when you read the cell with xlrd you don't get a df-object. so either make the single cell a dataframe or store it temorarily and make the dataframe afterwards.
something like this (untested) should do it.
all_data = [] # list
for file in files:
df = pd.read_excel(file, sheetname='sheet-1')
all_data.append(df.iloc[5,3])
all_data = pd.DataFrame(all_data) # dataframe
all_data.to_excel('all_data.xlsx')
or one could use other libraries as well to make the same, like openpyxl for example.

Write to an existing excel file using Openpyxl starting in existing sheet starting at a specific column and row

I have been searching this question to write in an existing excel sheet starting from specific row and column however methods like dataframe_to_rows is not writing from a specific position in a cell.
I am now using a custom loop to write this however was wondering if there is a better approach.
The loops works like this
import pandas as pd
import numpy as np
from openpyxl import load_workbook
from openpyxl.utils import get_column_letter
df = pd.DataFrame(np.random.randn(20, 4), columns=list('ABCD'))
file = "C:\\somepath\\some_existing_file.xlsx"
wb = load_workbook(filename=file, read_only=False)
ws = wb['some_existing_sheet']
##Fill up the row and column needed
stcol = 5
strow = 5
## Writing the column header
for c in range(0,len(df.columns)):
ws[get_column_letter(c+stcol)+str(strow)].value = df.columns[c]
## Writing the data
for r in range(0,len(df)):
for c in range(0,len(df.columns)):
ws[get_column_letter(c+stcol)+str(strow+r+1)].value = df.iloc[r][c]
wb.save(file)
Please let me know if there is a better way to write to specefic position in a cell. By any chance if this turns out to be duplicate question, happy to merge in the original thread.
I do have another approach however with xlsx writer but this removes all other data from existing sheet
import win32com.client as win32
excel = win32.gencache.EnsureDispatch('Excel.Application') # opens Excel
writer = pd.ExcelWriter(file', engine='xlsxwriter')
df.to_excel(writer, sheet_name='abc', startrow=5, startcol=5,index=False)
writer.save()

Instead of
ws[get_column_letter(c+stcol)+str(strow)]
you can use
ws.cell(column=c+stcol, row=strow)

Find range of filled contents in Excel worksheet

I have an Excel 2016 Book.xlsm. In the worksheet testsheet, the cells in the range A1:Y150 are filled with text or number contents. The upper-left cell is always A1.
I am using python v3 xlwings to open the Excel file.
import xlwings as xw
Book_name = 'C:/Users/name/Book.xlsm'
sheet_name = 'testsheet'
wb = xw.Book(Book_name)
sht = wb.sheets[sheet_name]
How do I find out the range of cells that are filled with contents using python, which in this case is A1:Y150?

You can get the range filled with contents with used_range:
import xlwings as xw
filename = "test.xlsx"
wb = xw.Book(filename)
ws = wb.sheets["SheetX"]
a_range = ws.used_range.address
print(a_range)

If wb is defined as Excel Workbook, then this is a good way:
print (wb.sheets[sheet_name].api.UsedRange.Address)