python - Apply if-else function to each cell in a dataframe results in ambiguous exception

Question

I have a pandas dataframe like this:

index	a	b	c
1	1	12	15
2	5	15	16

question from:https://stackoverflow.com/questions/65871728/apply-if-else-function-to-each-cell-in-a-dataframe-results-in-ambiguous-exceptio

Answer 1

What you are looking for is pandas.DataFrame.applymap, which applies a function element-wise:

df.applymap(lambda x: -1 if x < low else (1 if x > high else 0))

The method pandas.DataFrame.apply applies a function along a given axis (default is column-wise).