Split string after comma without trailing whitespace

Question

As the title already says, I want to split this string

strsplit(c("aaa,aaa", "bbb, bbb", "ddd , ddd"), ",")

to that

[[1]]
[1] "aaa" "aaa"

[[2]]
[1] "bbb, bbb"

[[3]]
[1] "ddd , ddd"

Thus, the regular expression has to consider that no whitespace should occur after the comma. Could be a dupe, but was not able to find a solution by googling.

Answer 1

regular expression has to consider that no whitespace should occur after the comma

Use negative lookahead assertion:

> strsplit(c("aaa,aaa", "bbb, bbb", "ddd , ddd"), ",(?!\\s)", perl = TRUE)
[[1]]
[1] "aaa" "aaa"

[[2]]
[1] "bbb, bbb"

[[3]]
[1] "ddd , ddd"

,(?!\\s) matches , only if it's not followed by a space