CODEWITHSUNDEEP
regex
E235
E235

Reputation: 13500

How to find all strings with length 5 that contain exactly one number and 4 letters

I need regex to count strings with length of 5 that contain exactly one number (0-9) and 4 letters (a-z).

I succeed to find only letters with ^[a-z]{5}$ but I don't know can I tell it find strings that has exactly one number.

For example:

jlwk6    -> one number
bjkgp
5fm8s
x975t
k88q5
zl796
qm9hb    -> one number
h6gtf    -> one number
9rm9p
jwzw2    -> one number

Total: 4

Upvotes: 1

Views: 370

Answers (3)

Gilles Quénot
Gilles Quénot

Reputation: 185580

With Perl :

$ perl -lne '
    $count = () = /\d/g;
    $gc += $count if $count == 1;
    END{print "Total $gc"}
' file

Output :

Total 4

Upvotes: 0

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 627317

You may use

^(?=.{5}$)[a-z]*\d[a-z]*$

See the regex demo

Details

  • ^ - start of string
  • (?=.{5}$) - there must be 5 chars (other than line break chars) in the string
  • [a-z]* - 0+ lowercase ASCII letters
  • \d - a digit
  • [a-z]* - 0+ lowercase ASCII letters
  • $ - end of string.

To extend the solution to N digits, use

^(?=.{5}$)[a-z]*(?:\d[a-z]*){N}$

Here, [a-z]*(?:\d[a-z]*){N} will match 0+ letters and then N occurrences of a digit followed with 0+ letters.

Upvotes: 2

Nikolas
Nikolas

Reputation: 44476

Use the following Regex:

^[a-z]*\d[a-z]*?(?<=^.{5}$)

Demo at Regex101.

  • [a-z]* matches any number of a-z characters before a number \d.
  • [a-z]*? matches any number of a-z characters afterward.
  • (?<=^.{5}$) is a positive lookback - it assures that there are 5 characters exactly between the start and end ^.{5}$.

Upvotes: 0

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