Replace all Trues in a boolean dataframe with index valule

问题

How can I replace all cells in a boolean dataframe (True/False) with the index name of that cell, when "True"? For example:

df = pd.DataFrame(
    [
        [False, True],
        [True, False],

    ],
    index=["abc", "def"],
    columns=list("ab")
)

comes out as:

df = pd.DataFrame(
    [
        [False, abc],
        [def, False],

    ],
    index=["abc", "def"],
    columns=list("ab")
)

回答1:

Use df.mask:

Replace values where the condition is True.

df.mask(df,df.index)

---

         a      b
abc  False    abc
def    def  False

来源：https://stackoverflow.com/questions/60703065/replace-all-trues-in-a-boolean-dataframe-with-index-valule