data frame columns formating

Question

I have multiple data sets which is concatenated in one master file using code below.

all_data = pd.DataFrame()
dfs = (pd.read_excel(f, index_col=0, skiprows=8, skipfooter=1, usecols=[0,1])
           for f in filenames)
all_data = pd.concat(dfs, axis=1)

The data looks in "each file" looks like these:(attached) ID VALUE

Concatenated master file now has like this:

ID value  value value value value value value value 

However, we would like to rename the each value in master file to have the file name such as :

Basically replacing the default col in data frame(value) to file names as individual col instead. Please guide.

Answer 1

You can change column names by simply setting the df.columns attribute to some other list. In this case, it looks like your list would be ['ID',file1,file2,...]

Since those filenames are included in the path in your filenames list, we can pull out just the filename and make a new list with those.

columns = list()
for path in filenames: #loop through your filenames list
    file = path.split('\\')[-1] #this splits the path by the '\' character, and returns the last element, so the filename. You need the double-slash since the slash is the escape character from the string, or whatever they call it.
    file = file[:-4] # the file has the .xls on the end. this removes the last 4 characters
    columns.append(file)
all_data.columns = columns #all_data is our dataframe, and all_data.columns is the attribute of the dataframe that contains the column names. Changing this object to our columns list that we made will change the column names in the dataframe.