[R] Matrix operations please help

[Uwe Ligges]

See ?reshape

Uwe Ligges


Srinivas Iyyer wrote:
> Dear Group, 
> 
> I have a matrix  (157 X 157 ) with correlation values.
> I want to convert the unique elements into a long list
> so that I can add an extra variable and plot them. 
> 
> Example:
> 
>       A   B   C   D 
> 
> alfa 1   0.3  0.8  -0.3
> 
> beta 0.2  1  -0.3  0.4
> 
> echo 0.9 -0.3  1   0.5
> 
> tang -0.5 0.5  0.4  1
> 
> 
> I want to convert into this form:
> 
> 
> alfa  A  1
> alfa  B  0.3
> alfa  C  0.8
> alfa  D  -0.3
> beta  A 0.2
> beta  B 1
> beta  C -0.3
> beta  D 0.4
> .......
> 
> and so on. 
> 
> 
> I will add another variable afterwards:
> var1  var2 corr   var3
> alfa  A  1    grp1
> alfa  B  0.3  grp1
> alfa  C  0.8  grp2
> alfa  D  -0.3 grp3
> beta  A 0.2   grp3
> beta  B 1     grp2
> beta  C -0.3  grp1
> beta  D 0.4   grp2
> ........ and so on....
> 
> 
> I am sure there should be a way.. but I am completely
> clueless.. 
> Can any one help me please. 
> 
> thanks
> srini
> 
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