calpeda wrote:
> thank you,
> but I m importing data from a txt file and I have a matrix of n*1
> The function str seems to work only from 1*n
>
>
you see, it would help if you provided more details from the start. you
may still need to do it; it seems that both solutions you were given
(mine and the substr one) work for both n*1 and 1*n matrices:
# 5*1
(strings = matrix(as.character(sample(10^6, 5)), ncol=1))
substr(strings, 1, 4)
substr(t(strings), 1, 4)
with a fixed pattern of four digits from the beginning of the string,
the substr solution is better -- simpler and a few times faster.
vQ
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