Question

I imported the 3rd sheet in a xlsx file, which contains 3 columns of data, using

import["e:/temp/15c.xlsx"][[3]]

The data looks like {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}. I wanted to do curve fitting for just one column of data, such as {1, 4, 7} or {2, 5, 8}. I tried

Fit[%[[1, All, All]], {1, x, x^2}, {x}]

but it didn’t work. Would anyone please suggest how to get any 1D data out of the 3D table imported? Thank you.

Answer 1

In[1]:= $list = {{1,2,3},{4,5,6},{7,8,9}};

In[2]:= $list[[All, 1]]

Out[2]= {1, 4, 7}

In[3]:= $list[[All, 2]]

Out[3]= {2, 5, 8}

In[4]:= $list[[All, 3]]

Out[4]= {3, 6, 9}

In[5]:= Fit[$list[[All, 2]], {1, x, x^2}, x] // Chop

Out[5]= -1. + 3. x