Conditionally split single cells

Question

I have this data.frame and I want to identify which cells from sample1$domain have "www", replace that with "" and strsplit the corresponding sample1$suffix. The data looks like this:

              domain         suffix
1              wbx2            com
2            redhat            com
3          something           com
4           gstatic            com
5               www googleapis.com
6       smartfilter            com

I have managed to tackle this as shown below but it changes the position of the row(s) (I would like it to stay at position 5) and given that it will run for million of cases, I don't think this is the most efficient way to do it.:

library("stringr")
sample1$domain <- ifelse(sample1$domain == "www", "", sample1$domain)
sample1[sample1$domain == "", c("domain", "suffix")] <- sample1[sample1$domain == "", c("suffix", "domain")]
y <- sample1$domain[sample1$suffix == ""]
z <- as.data.frame(unlist(str_split_fixed(y, "[.]", 2)))
colnames(z) <- c("domain", "suffix")
sample1 <- rbind(sample1, z)
sample1 <- subset(sample1, sample1$suffix != "")
rownames(sample1) <- NULL
sample1 
#             domain suffix
#1              wbx2    com
#2            redhat    com
#3         something    com
#4           gstatic    com
#5       smartfilter    com
#6        googleapis    com

DATA

sample1 <- structure(list(domain = c("wbx2", "redhat", "something", 
"gstatic", "www", "smartfilter"), suffix = c("com", "com", "com", 
"com", "googleapis.com", "com")), .Names = c("domain", "suffix"
), row.names = c(NA, 6L), class = "data.frame")

score 1 · Accepted Answer · answered Mar 11 '16 at 14:33

We can create an index for values with "www". Then use that index to replace the site name and lastly the site suffix:

ind <- sample1$domain == "www"
sample1$domain[ind] <- sub("^(.*)\\..*", "\\1", sample1$suffix[ind])
sample1$suffix[ind] <- sub(".*\\.(.*)", "\\1", sample1$suffix[ind])
sample1
#        domain suffix
# 1        wbx2    com
# 2      redhat    com
# 3   something    com
# 4     gstatic    com
# 5  googleapis    com
# 6 smartfilter    com

This is great. My regex is still very elementary. Thank you – Sotos Mar 11 '16 at 14:43 — Sotos, Mar 11 '16 at 14:43

Conditionally split single cells

1 Answers1