How do you detect a "word" on a line that contains both letters and numbers?

I need a regex that detects a "word" on a line that contains both letters and numbers and is a certain length, e.g. 812d555c726d10c77b05cd164705665a. The goal is to detect lines that contain sha1 digests.

If a regex-only is too hard, a Ruby solu开发者_JAVA百科tion is OK.

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This should do it:

valid_sha1 = !((str =~ /\b[a-f0-9]{32,}\b/i).nil?)

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You can use the following regular expression.

s =~ /^[a-f0-9]{32,32}$/i

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Both the other answers require the line begin with the SHA1. If the sha1 can be anywhere in the line, remove the ^

/[a-f0-9]{32}/i

You also don't need the second 32 in the curly braces, as if you only specify one number, it must match exactly that many.

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If you really want to require that the word consist of BOTH letters and numbers (as you ask above), then you can use positive lookahead:

sha_array = line.scan(/(?=.{0,31}\d)(?=.{0,31}[a-f])\b[\da-f]{32}\b/i)

The (?= checks a condition in advance, without consuming anything.