R for loop execute last line before running previous lines - r

Question

I have several text files and I read them in R as data frames. When I put those data frames in a list and do analysis in a for loop. It seems the code is not run line by line. If I add some code at the end of the loop, which may cause an error, the codes before it will not run in the for loop. Any one help to explain this for me?
below is my code:
rm(list=ls())
graphics.off()
#cost.seq = 10^seq(2, -3, length = 20)
k=7
error = data.frame(cv = c(1:k))
train.error = data.frame(cv = c(1:k))
report.rows = 3
report.name = "rda"
source("scriptd_stats01_read_feature.R")
source("scriptd_stats01_read_feature_fc.R")
source("scriptd_stats02_cv_functions.R")
multimodal.feature = scale(cbind(spm.vbm, alff, reho, label.fa, tract.fa, tract.md))
feature.list = list(spm.vbm, alff, reho, label.fa, tract.fa, tract.md, fc, multimodal.feature)
library(reshape2)
for (i.feature in 1:length(feature.list)) {
print("loop:")
print(i.feature)
brain.feature = scale(feature.list[[i.feature]])
df.all = cbind(subject.info[,-1], brain.feature)
report = data.frame(group = c("hc vs trauma", "ptsd vs trauma", "hc vs ptsd"), acc=rep(NA, report.rows),sensi=rep(NA,report.rows),speci=rep(NA,report.rows))
report.sd = data.frame(group = c("hc vs trauma", "ptsd vs trauma", "hc vs ptsd"), acc=rep(NA, report.rows),sensi=rep(NA,report.rows),speci=rep(NA,report.rows))
# ---------------------select data for ptsd 0 and 1 :---------------------
df.subset = df.all[df.all$ptsd==0|df.all$ptsd==1,]
print("dimension for subset dataset")
print(dim(df.subset))
print(table(df.subset$ptsd))
x = model.matrix(df.subset$ptsd~., df.subset)
y = df.subset$ptsd
print(dim(x))
set.seed(333)
cv.result = rda.cv.fun(x[,-1], y, k)
result = cv.result[[1]]
train.result = cv.result[[2]]
print(result)
print(train.result)
print("####")
print(colMeans(result, na.rm=T))
report[1,-1] = colMeans(result,na.rm=T)
report.sd[1,-1] = apply(result, 2, function(x)sd(na.omit(x)))
total.report = melt(report, id = ("acc", "sensi", "speci"))
print(total.report)
}
when I comment the last 2 lines in the for loop, it runs without error, and it print loop 1 2 3 to 8. But when I uncomment them, the previous codes did not run (no values are printed) and I got the error below:
Error: unexpected ',' in:
"
total.report = melt(report, id = ("acc","
Execution halted
This is very weird, as it seems the last two lines were executed before previous lines in the for loop.