CODEWITHSUNDEEP
rregexgsub
Mark Davies
Mark Davies

Reputation: 940

Use gsub to extract the first integer number

I'd like to use gsub to remove characters from a filename.

In the example below the desired output is 23

digs = "filepath/23-00.xlsx"

I can remove everything before 23 as follows:

gsub("^\\D+", "",digs)
[1] "23-00.xlsx"

or everything after:

gsub("\\-\\d+\\.xlsx$","", digs)
[1] "filepath/23"

How do I do both at the same time?

Upvotes: 3

Views: 519

Answers (2)

akrun
akrun

Reputation: 886968

We could use | (OR) i.e. match characters (.*) till the / or (|), match the - followed by characters (.*), replace with blank ("")

gsub(".*/|-.*", "", digs)
[1] "23"

Or just do parse_number

readr::parse_number(digs)
[1] 23

Upvotes: 5

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626709

You can just use a sub like

sub("^\\D+(\\d+).*", "\\1", digs)
# => [1] "23"

See the R demo. See the regex demo. Details:

  • ^ - start of string
  • \D+ - one or more non-digit chars
  • (\d+) - Group 1 (\1 refers to this group value): one or more digits
  • .* - any zero or more chars as many as possible.

Upvotes: 3

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