Why is this pandas dataframe not getting multiplied?-CodePudding

I have this Pandas dataframe:

BTC_USD_rates = {
    "Open": {"01/01/2022": 46217.5, "02/01/2022": 47738.7, "03/01/2022": 47293.9, "04/01/2022": 46435.7, "05/01/2022": 45833.1, "06/01/2022": 43431.6, "07/01/2022": 43097.9, "08/01/2022": 41551.3},
    "Low": {"01/01/2022": 46217.5, "02/01/2022": 46718.2, "03/01/2022": 45704.0, "04/01/2022": 45602.1, "05/01/2022": 42535.1, "06/01/2022": 42481.1, "07/01/2022": 40810.0, "08/01/2022": 40574.3},
    "High": {"01/01/2022": 47917.6, "02/01/2022": 47944.9, "03/01/2022": 47556.0, "04/01/2022": 47505.4, "05/01/2022": 47019.4, "06/01/2022": 43772.3, "07/01/2022": 43127.7, "08/01/2022": 42304.4},
    "Close": {"01/01/2022": 47738.0, "02/01/2022": 47311.8, "03/01/2022": 46430.2, "04/01/2022": 45837.3, "05/01/2022": 43425.9, "06/01/2022": 43097.5, "07/01/2022": 41546.7, "08/01/2022": 41672.0},
    "Volume": {"01/01/2022": 31239, "02/01/2022": 27020, "03/01/2022": 41062, "04/01/2022": 55589, "05/01/2022": 83744, "06/01/2022": 63076, "07/01/2022": 88358, "08/01/2022": 52544},
}
df1 = pd.DataFrame.from_dict(BTC_USD_rates)
df1
            Open    Low     High    Close   Volume
01/01/2022  46217.5 46217.5 47917.6 47738.0 31239
02/01/2022  47738.7 46718.2 47944.9 47311.8 27020
03/01/2022  47293.9 45704.0 47556.0 46430.2 41062
04/01/2022  46435.7 45602.1 47505.4 45837.3 55589
05/01/2022  45833.1 42535.1 47019.4 43425.9 83744
06/01/2022  43431.6 42481.1 43772.3 43097.5 63076
07/01/2022  43097.9 40810.0 43127.7 41546.7 88358
08/01/2022  41551.3 40574.3 42304.4 41672.0 52544

I need to multiply it by the Close column of this other dataframe df2 as follows:

new_rates
            Open    Low     High    Close
01/01/2022  1.4732  1.4732  1.4732  1.4732
02/01/2022  1.4732  1.4732  1.4732  1.4732
03/01/2022  1.4650  1.4583  1.4763  1.4732
04/01/2022  1.4719  1.4651  1.4784  1.4669
05/01/2022  1.4669  1.4669  1.4669  1.4669
06/01/2022  1.4717  1.4708  1.4854  1.4817
07/01/2022  1.4819  1.4733  1.4849  1.4741
08/01/2022  1.4741  1.4741  1.4741  1.4741

df2 = new_rates['Close']
df2

01/01/2022    1.4732
02/01/2022    1.4732
03/01/2022    1.4732
04/01/2022    1.4669
05/01/2022    1.4669
06/01/2022    1.4817
07/01/2022    1.4741
08/01/2022    1.4741
Name: Close, dtype: float64

But when I run this line of code I always end up having df1 with the same result as if I was multiplying all of its elements by 1:

df1.mul(df2, axis = 0)
df1

            Open    Low     High    Close   Volume
01/01/2022  46217.5 46217.5 47917.6 47738.0 31239
02/01/2022  47738.7 46718.2 47944.9 47311.8 27020
03/01/2022  47293.9 45704.0 47556.0 46430.2 41062
04/01/2022  46435.7 45602.1 47505.4 45837.3 55589
05/01/2022  45833.1 42535.1 47019.4 43425.9 83744
06/01/2022  43431.6 42481.1 43772.3 43097.5 63076
07/01/2022  43097.9 40810.0 43127.7 41546.7 88358
08/01/2022  41551.3 40574.3 42304.4 41672.0 52544

What am I missing here?

CodePudding user response：

Your df1 variable isn't being altered in memory by the function attribute .mul() Instead it returns the result of the multiplication.

What you need to do is reassign df1 like so,

df1 = df1.mul(df2, axis = 0)

and your df1 will be altered