df.loc[~df["C"].isna(), ("A", "B")] = "01"
df.loc[~df["C"].isna(), "F"] = df["E"] 

df.loc[~df["C"].isna(), ("A", "B", "F")] = "01", "01", df["E"]

with open(“xxx.csv”) as f:
    line = f.readline()
    while line:
        if line.strip() == “A,B,C,D”:
            break
        line = f.readline()
    df = pd.read_csv(f)

with open("xxx.csv") as f:
    data = []
    keyword_found = False
    for line in f:
         if keyword_found:
             data.append(line.strip().split(','))
         if line.startswith("keyword"):
             keyword_found = True
             data.append(line[len("keyword"):].strip().split(','))
df = pd.DataFrame(data)

row_filter = (df["D"] != "") & (~df["D"].isna())
df.loc[row_filter, "H"] = df["G"]
df.loc[row_filter, ("A", "B", "C", "G")] = 'Data1', 'Data2', '', ''
df.loc[row_filter, "F"] += 1