CODEWITHSUNDEEP
pythonpandasdataframe
pandasnew123455
pandasnew123455

Reputation: 25

Append python dataframe not appending properly

I have the following code:

import pandas as pd
df2 = pd.DataFrame(dataset)

df = pd.read_excel (r'C:/adhoc/test.xlsx')

df.append(df2,ignore_index=True)

# Create a Pandas Excel writer using XlsxWriter as the engine.
writer = pd.ExcelWriter(r'C:/adhoc/test.xlsx', engine='xlsxwriter')

# Convert the dataframe to an XlsxWriter Excel object.
df.to_excel(writer, sheet_name='Sheet1')

# Close the Pandas Excel writer and output the Excel file.
writer.save()

I am trying to take df2 (the current dataset) and append it into the already exiting data (df) and write that all back into the file. Essentially take the new data and append it to the bottom of the sheet. When I run this code all it does it add an extra index column beside the already exiting index column

Upvotes: 0

Views: 1084

Answers (3)

Michael Myrick
Michael Myrick

Reputation: 11

I'm having a similar problem as the original poster and I've arrived at I must not be appending my data properly or I'm not saving my file...problem is the solutions on the web are not seeming to work and/or Imma nub!

My program is supposed to append the last row of what I'm pulling into an excel sheet. Building a log.

only problem = it just saves over the data there or just creates a new excel sheet which it puts the data into...so that all i have the 1 row of data with the proper column names.

from sqlalchemy import false import yfinance as yf import pandas as pd from openpyxl import load_workbook import schedule import time from playsound import playsound

def func():

schedule.every(1).minutes.do(func)

while(True): schedule.run_pending() time.sleep(60)

spy = yf.Ticker('spy')

spy_history = spy.history(period="max")
spy_history = spy.history(start="2022-10-17", end="2022-10-19",interval="1m", actions = False)
spy_history = spy.history(start="2022-10-17", end="2022-10-19",interval="1m",prepost = True, actions = False)

pd.options.display.width = 0
pd.set_option("display.max_rows",50)

df = spy_history
most_recent = df.tail(1)
most_recent.to_excel('spyder.xlsx', index = False, columns=['Open', 'High', 'Low', 'Close', 'Volume'])

print (spy_history)
print (df.iloc[-1,-1])
mike = df.iloc[-1,-1]

if mike >=0:
    playsound('imp.wav')

Upvotes: 1

AarónRF
AarónRF

Reputation: 31

The method "append" doesn't change the dataframe, instead it returns another dataframe with the data of both dataframes. Therefore, you have to save the new dataframe in a variable. The code should resemble the following:

    df2 = df.append(df2, ignore_index=True)
    df2.to_excel('mi_file.xlsx', sheet_name = 'Sheet1')

Upvotes: 0

Patrick Bormann
Patrick Bormann

Reputation: 749

If you are feeling fine with a third merged data frame this produced a working solution: df1 = pd.concat([df, df2], ignore_index=True) instead of append. The solution lies in creating a new variable it doesnt matter if its append or concat, but with concat it seems a little bit clearer I'll guess.

Upvotes: 1

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