`assign` function and strings [duplicate]

Question

df = pd.DataFrame({"A": ["A1", "A2"], "B" : [1, 2]}

and list of strings: l = ["C", "D"]. I would like to add two columns to df as follows using assign function:

df = df.assign(l[0] = df["A"])

but I got an error "Keyword can't be an expression". What can I do?

Answer 1

You need to use a dict because l[0] is not a valid variable name:

df = df.assign(**{l[0]: df['A']})
print(df)

# Output
    A  B   C
0  A1  1  A1
1  A2  2  A2

Answer 2

Your question is a bit vague. Is this what you want?

df[l[0]] = df["A"]
df[l[1]] = df["A"]