Substracting values from different DataFrame

Question

I got two DataFrames and Want to substract.

df1:

              Val1         Val2      Val3       
0  -27 -0.8  -6.786321    -7.024615 -13.946589  
1  -27 -0.9  -5.746795    -5.804550 -11.576365  
2  -27 -1.0  -4.624857    -4.372321  -9.103681  
3  -27 -1.2  -2.685832    -2.418888  -5.057056  
4  -27 -1.4  -1.445561    -1.389468  -2.622357

df2:

       Bench
0      0.4601
1     -5.3336
2     -6.0163
3     -4.1776
4     -2.3472

As I have the same indexes, I tried to do: df1-df2, but it didn't work.

Therefore I've tried to use another way:

   headers = list(df1.columns.values)
   filtr_headers = filter(lambda x: x!='',headers)
         for i in filtr_headers:
                df1['%s' %(i)] = df1['%s' %(i)] - df2['Bench']

But I'm getting in return Dataframe with NaN values. I don't know why it's happening. Any hints will be higly appreciated.

Ami Tavory · Accepted Answer · 2016-08-11 19:16:56Z

1

You can use pd.DataFrame.sub, like this:

In [113]: df1.sub(df2.Bench.values, axis=0)
Out[113]: 
                Val1      Val2       Val3
0 -27 -0.8 -7.246421 -7.484715 -14.406689
1 -27 -0.9 -0.413195 -0.470950  -6.242765
2 -27 -1.0  1.391443  1.643979  -3.087381
3 -27 -1.2  1.491768  1.758712  -0.879456
4 -27 -1.4  0.901639  0.957732  -0.275157

answered Aug 11, 2016 at 19:16

Ami Tavory

76.7k13 gold badges152 silver badges196 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Monica Over a year ago

Thanks! It works out! Though I try to understand why my way of implementing is not working. s the problem with a different numbers of columns in these two Dataframes? I also want to skip two firs columns while subtracting. I've tried to do it by: df1.ix['Val1':].sub(df2.Bench.values, axis=0), but I'm getting error again.

Ami Tavory Over a year ago

@Monica You're welcome. About your first point - it attempts to do a join to subtract same-name columns, but there aren't any. About your second point - you have a strange index thing going on. Could I ask you to open a separate question about it? It's a separate question, and interesting in its own right. If you want, drop here a link to it, and I'll be happy to write there.

Ami Tavory Over a year ago

@Monica In any case, those are not columns, they're part of the index. Try ` df1.index = range(5)` and see what happens.

Monica Over a year ago

Thank you again for your explanation. You're totally right, they are indexes. btw Is there any possibility to talk to you on a private?

Monica Over a year ago

stackoverflow.com/questions/38934415/…

|

Pansy · Accepted Answer · 2016-08-11 19:18:38Z

0

You can use

pd.DataFrame(df1.values - df2.values)

answered Aug 11, 2016 at 19:18

Pansy

3301 gold badge5 silver badges13 bronze badges

Collectives™ on Stack Overflow

Substracting values from different DataFrame

2 Answers 2

6 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related