Selecting columns - dataframes, pandas

Question

How do you go about selecting a column in a Pandas Dataframe, where the column name depends on a value, which we have located in another dataframe ? For example, if [1,2,3..] are column names of dataframe 1 and [1,2,3..] are values of different cells in dataframe 2. How do you select a column in dataframe 1, by matching the column name with cell value in dataframe 2.

Answer 1

df1 = pd.DataFrame([list('abc')], [0], [1, 2, 3])
df2 = pd.DataFrame(dict(A=[2, 3, 1]))

df1

   1  2  3
0  a  b  c

df2

   A
0  2
1  3
2  1

df1[df2.A]

   2  3  1
0  b  c  a

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response to comment

df1.loc[0, df2.loc[0, 'A']]

'b'

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df1.at[0, df2.at[0, 'A']]

'b'

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df1.get_value(0, df2.get_value(0, 'A'))

'b'