Conditional method chaining in pandas

Question

Is there a simple general way to make a method conditional to an if-statement when using method chaining with pandas?

Mock example:

df = pd.DataFrame({'A':['one', 'two'], 'B':['one', 'two']})

change_to_numeric = False

df = (df
    .query("A == 'one'")
    .replace('one', 1)         # <-- Execute this row only "if change_to_numeric == True"
)

Thank you!

Answer 1

You can use pipe:

df = pd.DataFrame({'A':['one', 'two'], 'B':['one', 'two']})

change_to_numeric = False

df = (df
    .query("A == 'one'")
    .pipe(lambda d: d.replace('one', 1) if change_to_numeric else d)
)

output for change_to_numeric = False:

     A    B
0  one  one

output for change_to_numeric = True:

   A  B
0  1  1