add column to a dataframe in python pandas

Question

How do i loop through my excel sheet and add each 'Adjusted Close' to a dataframe? I want to summarize all adj close and make an stock indice.

When i try with the below code the dataframe Percent_Change is empty.

xls = pd.ExcelFile('databas.xlsx')
countSheets = len(xls.sheet_names)

Percent_Change = pd.DataFrame()

x = 0
for x in range(countSheets):
    data = pd.read_excel('databas.xlsx', sheet_name=x, index_col='Date')

    # Calculate the percent change from day to day
    Percent_Change[x] = pd.Series(data['Adj Close'].pct_change()*100,     index=Percent_Change.index)


 stock_index = data['Percent_Change'].cumsum()

Answer 1

unfortunately I do not have the data to replicate your complete example. However, there appears to be a bug in your code. You are looping over "x" and "x" is a list of integers. You probably want to loop over the sheet names and append them to your DF. If you want to do that your code should be:

import pandas as pd

xls = pd.ExcelFile('databas.xlsx')
# pep8 unto thyself only, it is conventional to use "_" instead of camelCase or to avoid longer names if at all possible
sheets = xls.sheet_names

Percent_Change = pd.DataFrame()

# using sheet instead of x is more "pythonic"
for sheet in sheets:
    data = pd.read_excel('databas.xlsx', sheet_name=sheet, index_col='Date')

    # Calculate the percent change from day to day
    Percent_Change[sheet] = pd.Series(data['Adj Close'].pct_change()*100, index=Percent_Change.index)

stock_index = data['Percent_Change'].cumsum()