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Re: Operations on RegularExpression matches

• To: mathgroup at smc.vnet.net
• Subject: [mg120015] Re: Operations on RegularExpression matches
• From: Heike Gramberg <heike.gramberg at gmail.com>
• Date: Tue, 5 Jul 2011 05:11:54 -0400 (EDT)
• References: <201107041044.GAA02505@smc.vnet.net>

Try using RuleDelayed:

StringReplace[string, RegularExpression["(^.)"] :> ToUpperCase["$1"]]

By using RuleDelayed (:>) instead of Rule (->), the right-hand side of the replacement rule isn't evaluated until after the rule is used.

Heike

On 4 Jul 2011, at 11:44, Jon Joseph wrote:

> All:
>
> I have string of all lower case letters:
>
> 	string = "this is a string"
>
> I wish to capitalize the first letter:
>
> 	StringReplace[string, StartOfString ~~ x_ -> ToUpperCase[x]]  (* Does want I want *)
>
> Now I try to do the same thing using RegularExpression:
>
> 	StringReplace[string, RegularExpression["(^.)"] -> ToUpperCase["$1"]]
>
> which fails (returns original string without capitalization).
>
> I know the match is occurring since
>
> 	StringReplace[string, RegularExpression["(^.)"] -> ToUpperCase["$1X"]]
>
> returns
>
> 	"tXhis is a string"
>
> What am I missing about using the matched part of a regular expression?
>
> Thanks.
>

• References:
  • Operations on RegularExpression matches
    • From: Jon Joseph <josco.jon@gmail.com>