How to transform first four rows of dataframe to column names without using loop?

Question

I have the CSV-file and I need to combine its first four rows to headers (and first header needs to be empty). I tried to do that with Pandas and code works but I know that looping through dataframe is not recommended. Is there better way to do it?

import pandas as pd

df = pd.read_csv(file_path, header=None)
df_headers = df[0:4]
df = df.drop(index=[0,1,2,3,])
header_list = []

for column in df_headers:
    header_list.append(df_headers[column].str.cat(sep=' '))

header_list[0] = ""
df.columns = header_list

df.to_csv('output.csv',index=False)

Answer 1

>>> columns_mapping = dict(zip(range(df.shape[1]), df.iloc[:4].astype(str).apply(' '.join).to_list()))
>>> df = df.iloc[4:].rename(columns=columns_mapping)