CODEWITHSUNDEEP
regexr
user1926173
user1926173

Reputation:

Extract 2nd to last word in string

I know how to do it in Python, but can't get it to work in R

> string  <- "this is a sentence"
> pattern <- "\b([\w]+)[\s]+([\w]+)[\W]*?$"
Error: '\w' is an unrecognized escape in character string starting "\b([\w"
> match   <- regexec(pattern, string)
> words   <- regmatches(string, match)
> words
[[1]]
character(0)

Upvotes: 2

Views: 5369

Answers (3)

QuentinJS
QuentinJS

Reputation: 322

Python non regex version

    spl = t.split(" ")
    if len(spl) > 0:
        s = spl[len(spl)-2]

Upvotes: 0

eddi
eddi

Reputation: 49448

sub('.*?(\\w+)\\W+\\w+\\W*?$', '\\1', string)
#[1] "a"

which reads - be non-greedy and look for anything until you get to the sequence - some word characters + some non-word characters + some word characters + optional non-word characters + end of string, then extract the first collection of word characters in that sequence

Upvotes: 6

mengeln
mengeln

Reputation: 331

Non-regex solution:

string  <- "this is a sentence"
split <- strsplit(string, " ")[[1]]
split[length(split)-1]

Upvotes: 5

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