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Import a two-column table and set them to x[n], y[n]

Hung Phan, UCSB
Posted 11 years ago
Hello,

I want to import a two column table of numeric data to Mathematica and set each number to two vector variables x and y.
For example the below table:
1  0.1
2  0.5
3  0.7
4  12
5  -3
After importing I want to set x[1]=1, x[2]=2...x[5]=5; and y[1]=0.1, y[2]=0.5....y[5]=-3.

I know how to import the table but I can not figure out how to import it and set variable simultaneously.

Would you please help me out? Thanks.
POSTED BY: Hung Phan
4 Replies
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Mike Bohac
Mike Bohac
Posted 11 years ago
This seems easier than that:

Assuming a table "mydata", then it can be dumped into variables just by selecting the columns:
  x = mydata[[All,1]]
  y = mydata[[All,2]]
POSTED BY: Mike Bohac
David Keith
David Keith
Posted 11 years ago
MapIndexed[] knows the part of the expression its function is acting on:
 In[1]:= data = Table[{n, n/10.}, {n, 5}];
 
 In[2]:= f[{xx_, yy_}, {n_}] := (x[n] = xx; y[n] = yy;)
 
 In[3]:= MapIndexed[f, data, {1}];
 
 In[4]:= {x[2], y[2]}
 
 Out[4]= {2, 0.2}
POSTED BY: David Keith
Hi over there, 

in the simplest way it is
 In[51]:= SetDirectory[NotebookDirectory[]]
 
 Out[51]= "N:\\Udo\\Abt_N"
 
 In[56]:= FilePrint[".\\test\\hungPhan.txt"]
 During evaluation of In[56]:=
 
 1 0.1
 2 0.5
3 0.7
4 12
5 -3

In[61]:= {x, y} = Transpose[Import[".\\test\hungPhan.txt", "Table"]]
During evaluation of In[61]:= Syntax::stresc: Unknown string escape \h.
During evaluation of In[61]:= Syntax::stresc: Unknown string escape \h.

Out[61]= {{1, 2, 3, 4, 5}, {0.1, 0.5, 0.7, 12, -3}}

In[59]:= x[[4]]
Out[59]= 4

In[60]:= y[[4]]
Out[60]= 12

Regards
Udo.
POSTED BY: Udo Krause
Bill Simpson
Bill Simpson
Posted 11 years ago
 In[1]:= Evaluate[
 Table[{x[i], y[i]}, {i, 1, 5}]] = {{1, .1}, {2, .5}, {3, .7}, {4, 12}, {5, -3}}
 
 Out[1]= {{1, 0.1}, {2, 0.5}, {3, 0.7}, {4, 12}, {5, -3}}
 
 In[2]:= x[3]
 
 Out[2]= 3
 
In[3]:= y[2]

Out[3]= 0.5
Watch out if you do that more than one time. You might look up Clear and Evaluation->Quit Kernel->Local->Quit
POSTED BY: Bill Simpson
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