[R] reshaping a large dataframe in R
jean-philippe
jeanphilippe.fontaine at gssi.infn.it
Mon Nov 28 10:06:56 CET 2016
dear all,
I have a dataframe of 500 rows and 4004 columns that I would like to
reshape to a dataframe of 500500 rows and 4 columns. That is from this
dataframe:
V1 V2 V3 V4 ... V4001 V4002 V4003 V4004
1 2 3 4 ... 4001 4002 4003 4004
1 2 3 4 ... 4001 4002 4003 4004
1 2 3 4 ... 4001 4002 4003 4004
... ... ... ... ... ... ... ... ... ... ... ... ...
1 2 3 4 ... 4001 4002 4003 4004
I would like :
V1 V2 V3 V4
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
... ... ... ... ... ... ... ... ...
4001 4002 4003 4004
4001 4002 4003 4004
4001 4002 4003 4004
... ... ... ... ...
4001 4002 4003 4004
I tried already to use y=matrix(as.matrix(dataGaus[[1]]),500500,4)
(where dataGaus is my dataframe) but it doesn't give the expected
result. I tried also to use reshape but I can't manage to use it to
reproduce the result (and I have been through lot of posts on
StackOverflow and on the net). In python, we can do this with a simple
command numpy.array(dataGaus[[1]]).reshape(-1,4). For some reasons, I am
doing my analysis in R, and I would like to know if there is a function
which does the same thing as the reshape(-1,4) of numpy in Python?
Thanks in advance, best
Jean-Philippe
--
Jean-Philippe Fontaine
PhD Student in Astroparticle Physics,
Gran Sasso Science Institute (GSSI),
Viale Francesco Crispi 7,
67100 L'Aquila, Italy
Mobile: +393487128593, +33615653774
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