Drop level from one specific column

Question

Inspired by Pandas: drop a level from a multi-level column index?

I have a multilevel dataframe:

  | l |   a   |
  +---+---+---+
  |   | b | c |
--+---+---+---+
0 | a ¦ 1 | 2 |
1 | b ¦ 3 | 4 |

I need to flatten the column a at level 0

So that it would look like:

  +---+---+---+
  | l | b | c |
--+---+---+---+
0 | a ¦ 1 | 2 |
1 | b ¦ 3 | 4 |

df.columns = df.columns.droplevel() produces

  +---+---+---+
  |   | b | c |
--+---+---+---+
0 | a ¦ 1 | 2 |
1 | b ¦ 3 | 4 |

I am struggling to produce a toy example as well

Answer 1

Try this

df.columns = [c[-1] for c in df.columns]