[R] grep problem decimal points looping

RCulloch
Tue, 10 Aug 2010 13:17:32 -0000

Hi R Users,

I have been trying to work out how to rename column names using grep,
basically I have generated these column names using tapply:

  [1] "NAME"  "X1.1"  "X2.1"  "X3.1"
"X4.1"  "X5.1"  "X6.1"  "X7.1"
"X8.1"
 [10] "X1.2"  "X2.2"  "X3.2"  "X4.2"
"X5.2"  "X6.2"  "X7.2"  "X8.2"
"X1.3"
 [19] "X2.3"  "X3.3"  "X4.3"  "X5.3"
"X6.3"  "X7.3"  "X8.3"  "X1.5"
"X2.5"
 [28] "X3.5"  "X4.5"  "X5.5"  "X6.5"
"X7.5"  "X8.5"  "X1.6"  "X2.6"
"X3.6"
 [37] "X4.6"  "X5.6"  "X6.6"  "X7.6"
"X8.6"  "X1.8"  "X2.8"  "X3.8"
"X4.8"
 [46] "X5.8"  "X6.8"  "X7.8"  "X8.8"
"X1.9"  "X2.9"  "X3.9"  "X4.9"
"X5.9"
 [55] "X6.9"  "X7.9"  "X8.9"  "X1.10"
"X2.10" "X3.10" "X4.10" "X5.10"
"X6.10"
 [64] "X7.10" "X8.10" "X1.12" "X2.12"
"X3.12" "X4.12" "X5.12" "X6.12"
"X7.12"
 [73] "X8.12" "X1.13" "X2.13" "X3.13"
"X4.13" "X5.13" "X6.13" "X7.13"
"X8.13"
 [82] "X1.14" "X2.14" "X3.14" "X4.14"
"X5.14" "X6.14" "X7.14" "X8.14"
"X1.15"
 [91] "X2.15" "X3.15" "X4.15" "X5.15"
"X6.15" "X7.15" "X8.15" "X1.16"
"X2.16"
[100] "X3.16" "X4.16" "X5.16" "X6.16"
"X7.16" "X8.16" "X1.17" "X2.17"
"X3.17"
[109] "X4.17" "X5.17" "X6.17" "X7.17"
"X8.17" "X1.18" "X2.18" "X3.18"
"X4.18"
[118] "X5.18" "X6.18" "X7.18" "X8.18"
"X1.19" "X2.19" "X3.19" "X4.19"
"X5.19"
[127] "X6.19" "X7.19" "X8.19" "X1.20"
"X2.20" "X3.20" "X4.20" "X5.20"
"X6.20"
[136] "X7.20" "X8.20" "X1.21" "X2.21"
"X3.21" "X4.21" "X5.21" "X6.21"
"X7.21"
[145] "X8.21" "X1.22" "X2.22" "X3.22"
"X4.22" "X5.22" "X6.22" "X7.22"
"X8.22"
[154] "X1.23" "X2.23" "X3.23" "X4.23"
"X5.23" "X6.23" "X7.23" "X8.23"
"X1.24"
[163] "X2.24" "X3.24" "X4.24" "X5.24"
"X6.24" "X7.24" "X8.24" "X1.25"
"X2.25"
[172] "X3.25" "X4.25" "X5.25" "X6.25"
"X7.25" "X8.25" "X1.26" "X2.26"
"X3.26"
[181] "X4.26" "X5.26" "X6.26" "X7.26"
"X8.26" "X1.27" "X2.27" "X3.27"
"X4.27"
[190] "X5.27" "X6.27" "X7.27" "X8.27"
"X1.28" "X2.28" "X3.28" "X4.28"
"X5.28"
[199] "X6.28" "X7.28" "X8.28" "X1.29"
"X2.29" "X3.29" "X4.29" "X5.29"
"X6.29"
[208] "X7.29" "X8.29" "X1.30" "X2.30"
"X3.30" "X4.30" "X5.30" "X6.30"
"X7.30"
[217] "X8.30" "X1.31" "X2.31" "X3.31"
"X4.31" "X5.31" "X6.31" "X7.31"
"X8.31"
[226] "X1.32" "X2.32" "X3.32" "X4.32"
"X5.32" "X6.32" "X7.32" "X8.32"
"X1.33"
[235] "X2.33" "X3.33" "X4.33" "X5.33"
"X6.33" "X7.33" "X8.33"

What the names mean are behaviour.day the X is not important to the data, it
is the numbers I am trying to select on.

So I want to split the data by day i.e. selecting for the number after the
decimal.

I am using this code (where scananal is the data) with out looping so the
number following the decimal I change manually (NB the data have been
changed to character):

DAY <- grep("(X[[:digit:]]+).3",colnames(scananal))

However, this will select for day 3, 30, 31, 32, etc I have tried to use
fixed = TRUE, but that just returns integer(0). But if I use 30, it will
select only 30. Not sure what I'm doing wrong here, and I assumed that fixed
= T would fix this, but doesn't.

I have tried to loop this too, but with no luck, so if anyone can point me
in the right direction about how to loop using grep I would be most
grateful!

The main problem I have is where to put the loop, for example:

for(i in 1:33){
print(i)
DAY[[i]] <- grep("(X[[:digit:]]+).[[i]]",colnames(scananal))
}


which doesn't work, and no doubt there are obvious reasons for this! Any
help would be much appreciated,

All the best,

Ross






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