How to find first and last word of sentence with Regular Expression

[kcvinu]

Hi all,

How to find first and last word in a sentence with Regular expression ?. Sentence is the code from SciTE. For example if sentence is;

"For $i = 0 to 15" 

I need to extract "For from the sentence

And the same way i need last word from a sentence

"If Apple = 15 Then" 

I need "Then" from the sentence.

[water]

The most important thing for a working solution is to define the meaning of "word".

You need to define what delimits a word. Space, comma, bracket etc.

[mpower]

  On 3/11/2015 at 1:29 PM, kcvinu said:

Hi all,

How to find first and last word in a sentence with Regular expression ?. Sentence is the code from SciTE. For example if sentence is;

"For $i = 0 to 15" 

I need to extract "For from the sentence

And the same way i need last word from a sentence

"If Apple = 15 Then" 

I need "Then" from the sentence.

 

Give this a whirl:

$sentence = "For $i = 0 to 15"
$sentence2 = "If Apple = 15 Then"

$firstword = StringRegExp($sentence, "(?:^|(?:\.\s))(\w+)", 1)
$lastword = StringRegExp($sentence, "\s(\w+)$", 1)

ConsoleWrite($firstword[0] & @CRLF)
ConsoleWrite($lastword[0] & @CRLF)

$firstword = StringRegExp($sentence2, "(?:^|(?:\.\s))(\w+)", 1)
$lastword = StringRegExp($sentence2, "\s(\w+)$", 1)

ConsoleWrite($firstword[0] & @CRLF)
ConsoleWrite($lastword[0] & @CRLF)

Sources: http://lmgtfy.com/?q=regex+first+word+in+sentence    and     http://lmgtfy.com/?q=regex+last+word+in+sentence

Edited March 11, 2015 by mpower

[iamtheky]

$sentence = "For $i = 0 to 15"
$sentence2 = "If Apple = 15 Then"

msgbox( 0 , '' , _firstlast($sentence))
msgbox( 0 , '' , _firstlast($sentence2))



Func _firstlast($string)

$aString = stringsplit($string , " ")
return $aString[1] & @CRLF & $aString[ubound($aString) - 1]

EndFunc

[kcvinu]

I have googled a lot and tried something with the RegExp_GUI. Thanks for AutoIt for giving me a nice program for testing regular expresions.

@Water, In this case a word which separated with space only.

@boththose and @mpower, thanks. Let me try.

[jguinch]

#Include <Array.au3>

$sentence2 = "If Apple = 15 Then"

$words = StringRegExp($sentence2, "(?m)\W*(\w+).*?(\w+)\W*$", 1)
_ArrayDisplay($words)

Here is a small explanation :

(?m) : multiline mode. With this mode, ^ and $ operates on each line instead of the whole string

W* : any non-word character, 0 or more times

(w+) : capturing group. any word character, one or more times

.*? : anything, one or more times. ? takes the smallest occurence

$ : end of line or end of string

Edited March 11, 2015 by jguinch

[kcvinu]

@

jguinch, Thanks. There is more than one anser which needs to mark solved. What to do.

[water]

Mark the one which is easiest for you to underrstand.

[kcvinu]

@water,

Actually regular expression code is always horrible for me. So there is no easiest thing. I have googled a lot for what this "?" stands for . I didn't get any proper answer. So i have downloaded O'reilly's Regular expression Nutshell. And started reading. 

[jguinch]

kcvinu, I edited my code to add an explanation...

[mikell]

If you feel bad with regex, why don't you use the code from boththose ?

It works nice - if you just add a StringStripWS

$sentence = "    If Apple = 15 Then  "

msgbox( 0 , "" , _firstlast($sentence))

Func _firstlast($string)
  $aString = stringsplit(StringStripWS($string, 3) , " ")
  return $aString[1] & @CRLF & $aString[$aString[0]]
EndFunc

Edit

BTW in the case below all the codes on this page will fail 

$sentence = "   If Apple = 15 Then   ; this is a condition "

Edited March 11, 2015 by mikell

[kcvinu]

@

mikell, I think RegExp code works faster. And i had a wish to learn regular expression. May be it is harder. But i need to learn it. 

[mikell]

So...

#Include <Array.au3>

$sentence = "   If Apple = 15 Then   ; this is a condition "

$words = StringRegExp($sentence, "\s*(\w+)[^;]+\s(\w+);?.*", 3)
_ArrayDisplay($words)

[kcvinu]

@

mikell, So either Regular expression is for humans or you are an alien.  

[mikell]

Not an alien (so thinks my wife) but I've been a regex student for a long time - and I still am, and always will be  

[kcvinu]

@mikell Then please suggest me a good and free e-book or pdf book to learn regular expression. I am complete beginner.

[Melba23]

kcvinu,

I always recommend this site. But the learning curve is steep and stays that way - when mikell says "I've been a regex student for a long time " he really means it!

M23

[kcvinu]

@Melba23 , Thank you. I know that. 

[mikell]

I have 2 favorite sites : the one Melba mentioned, and this other one http://www.rexegg.com/

On both sites explanations are clear and understandable - very important condition when dealing with regex 

[kcvinu]

@Mikell, Thanks.