Creating a dataframe in pandas by multiplying two series together

2024/11/17 17:34:47

Say I have two series in pandas, series A and series B. How do I create a dataframe in which all of those values are multiplied together, i.e. with series A down the left hand side and series B along the top. Basically the same concept as this, where series A would be the yellow on the left and series B the yellow along the top, and all the values in between would be filled in by multiplication:

http://www.google.co.uk/imgres?imgurl=http://www.vaughns-1-pagers.com/computer/multiplication-tables/times-table-12x12.gif&imgrefurl=http://www.vaughns-1-pagers.com/computer/multiplication-tables.htm&h=533&w=720&sz=58&tbnid=9B8R_kpUloA4NM:&tbnh=90&tbnw=122&zoom=1&usg=__meqZT9kIAMJ5b8BenRzF0l-CUqY=&docid=j9BT8tUCNtg--M&sa=X&ei=bkBpUpOWOI2p0AWYnIHwBQ&ved=0CE0Q9QEwBg

Sorry, should probably have added that my two series are not the same length. I'm getting an error now that 'matrices are not aligned' so I assume that's the problem.

Answer

You can use matrix multiplication dot, but before you have to convert Series to DataFrame (because dot method on Series implements dot product):

>>> B = pd.Series(range(1, 5))
>>> A = pd.Series(range(1, 5))
>>> dfA = pd.DataFrame(A)
>>> dfB = pd.DataFrame(B)
>>> dfA.dot(dfB.T)0  1   2   3
0  1  2   3   4
1  2  4   6   8
2  3  6   9  12
3  4  8  12  16
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