Pandas/Python - update dataframe

Question

I have the following dataframe:

df:

          Wins     Ratio
id
234         10      None
143         32      None
678          2      None

I'm running a model to find out Ratio for each id. My model is finding Ratio, it is in another data frame, that looks like this:

result:

143
Wins     32
Ratio   987

However, I'm struggling to update df with ratio. I'm looking for a function that simply updates df for the id 143. Tryed to use the pd.dataframe.update() but seems it doesn't work that way (or I was unable to make it work). Can someone help on that?

I'm very sorry guys, I changed the dataframes but forgot to change the text. Now it is alright. — aabujamra
– aabujamra, Commented Jun 19, 2017 at 17:00

Scott Boston · Accepted Answer · 2017-06-19 17:07:47Z

1

Where:

df

Outputs:

     Wins Ratio
id             
234    10  None
143    32  None
678     2  None

And:

result

Outputs:

       143
Wins    32
Ratio   98

You can update df using combine_first:

df.replace('None',np.nan).combine_first(result.T)

Output:

     Wins  Ratio
143    32   98.0
234    10    NaN
678     2    NaN

answered Jun 19, 2017 at 17:07

Scott Boston

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1 Comment

aabujamra Over a year ago

I was able to do it using <code>results=pd.DataFrame(results).T</code> and <code>df=df.combine_first(results)</code>. Thanks for the combine_first tip

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