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fgr

Member

From: Italy

Registered: 2009-02-12

Posts: 20

About regular expression

I need to find a regular expression that matches words with three characters (and the first letter is upper). I don't know enough about regular expression for doing it myself. How can I do?

Cyrusm

Member

From: Bozeman, MT

Registered: 2007-11-15

Posts: 1,053

Re: About regular expression

take a look on google, this is a pretty basic regex.

http://www.regular-expressions.info/tutorial.html
http://www.amk.ca/python/howto/regex/
http://www.codeproject.com/KB/dotnet/regextutorial.aspx

that should be more than enough to get you started.

also, what language are you trying to make a regular expression for?  the syntax can be different from language to language.

Last edited by Cyrusm (2010-04-25 13:05:50)

---

Hofstadter's Law:
           It always takes longer than you expect, even when you take into account Hofstadter's Law.

Procyon

Member

Registered: 2008-05-07

Posts: 1,819

Re: About regular expression

Take a look at
http://www.grymoire.com/Unix/Regular.html#uh-9
and
http://www.grymoire.com/Unix/Regular.html#uh-13
and
http://www.grymoire.com/Unix/Regular.html#uh-8
echo 'you You Your' | sed 's/\<[[:upper:]][[:alpha:]]\{2\}\>/XXX/g'
you XXX Your

fgr

Member

From: Italy

Registered: 2009-02-12

Posts: 20

Re: About regular expression

also, what language are you trying to make a regular expression for?  the syntax can be different from language to language.

for Python and grep

Thanks to all for replies.

EDIT: I've found this:

grep '\<[A-Za-z]\{3\}\>'

But it matches both capital and lower case. However, it's a good beginning point. :-)

Last edited by fgr (2010-04-25 14:00:30)

Rip-Rip

Member

Registered: 2008-11-09

Posts: 32

Re: About regular expression

also, what language are you trying to make a regular expression for?  the syntax can be different from language to language.

for Python and grep

Thanks to all for replies.

EDIT: I've found this:

grep '\<[A-Za-z]\{3\}\>'

But it matches both capital and lower case. However, it's a good beginning point. :-)

try :

grep '\<[A-Z][a-z]\{2\}\>'

It will find all words of three letters, beginning with an uppercase character, and finishing with two lowercase characters.

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,294

Re: About regular expression

also, what language are you trying to make a regular expression for?  the syntax can be different from language to language.

for Python and grep

When I first saw Cyrusm's post, I thought he meant natural languages.  I thought that an interesting point I had never considered.  Almost every language I ever encounter is based on the Latin alphabet (or simple variations on it).  I realized I had no concept of how to deal with Greek, Syrillic, Arabic, Korean, and Various Japanese and Chinese alphabets.

Then I saw fgr's response as to programming language's, at which point I wondered if I had missed the point.

Without intending to hijack the thread, How do RE's work for languages that read right to left, or that may be more symbolic in nature?

---

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Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
How to Ask Questions the Smart Way

fgr

Member

From: Italy

Registered: 2009-02-12

Posts: 20

Re: About regular expression

[...]
try :

grep '\<[A-Z][a-z]\{2\}\>'

It will find all words of three letters, beginning with an uppercase character, and finishing with two lowercase characters.

it works fine, thanks.

Cyrusm

Member

From: Bozeman, MT

Registered: 2007-11-15

Posts: 1,053

Re: About regular expression

also, what language are you trying to make a regular expression for?  the syntax can be different from language to language.

for Python and grep

When I first saw Cyrusm's post, I thought he meant natural languages.  I thought that an interesting point I had never considered.  Almost every language I ever encounter is based on the Latin alphabet (or simple variations on it).  I realized I had no concept of how to deal with Greek, Syrillic, Arabic, Korean, and Various Japanese and Chinese alphabets.

Then I saw fgr's response as to programming language's, at which point I wondered if I had missed the point.

Without intending to hijack the thread, How do RE's work for languages that read right to left, or that may be more symbolic in nature?

hm. I never thought of it that way.  it might be something worth researching...

---

Hofstadter's Law:
           It always takes longer than you expect, even when you take into account Hofstadter's Law.

fgr

Member

From: Italy

Registered: 2009-02-12

Posts: 20

Re: About regular expression

also, what language are you trying to make a regular expression for?  the syntax can be different from language to language.

for Python and grep

When I first saw Cyrusm's post, I thought he meant natural languages.  I thought that an interesting point I had never considered.  Almost every language I ever encounter is based on the Latin alphabet (or simple variations on it).  I realized I had no concept of how to deal with Greek, Syrillic, Arabic, Korean, and Various Japanese and Chinese alphabets.
[...]

It's an interesting matter. But, we don't forget who makes international standards for any area of applicability is a western institution...

Last edited by fgr (2010-04-27 17:12:36)