[R] Extract part of vector

[jim holtman]

This should do it:

> txt
[1] "\nhttp://www.mysite.com/system/empty.asp?P=2&VID=default&SID=421384237289476&S=1&C=18631"
[2] "\nhttp://www.mysite.com/system/empty.asp?P=123&VID=default&SID=421384237289476&S=1&C=18643"
[3] "\nhttp://www.mysite.com/system/empty.asp?P=342&VID=default&SID=421384237289476&S=1&C=18634\n"
[4] "\nhttp://www.mysite.com/system/empty.asp?P=232&VID=default&SID=421384237289476&S=1&C=18645"
[5] "\nhttp://www.mysite.com/system/empty.asp?P=2345&VID=default&SID=421384237289476&S=1&C=18254"
[6] "\nhttp://www.mysite.com/system/empty.asp?P=257654&VID=default&SID=421384237289476&S=1&C=18732"
[7] "\nhttp://www.mysite.com/system/empty.asp?P=22&VID=default&SID=421384237289476&S=1&C=18637"
[8] "\nhttp://www.mysite.com/system/empty.asp?P=2463&VID=default&SID=421384237289476&S=1&C=18575\n"

> gsub("^.*asp.P=([[:digit:]]+).*$", '\\1', txt)
[1] "2"      "123"    "342"    "232"    "2345"   "257654" "22"     "2463"
>


On 8/13/07, Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:
> Dear R-users,
>
> How do I extract numbers between asp?P= and &VID from my txt vector? I have
> tried grep function with no luck.
>
> txt <- c("
> http://www.mysite.com/system/empty.asp?P=2&VID=default&SID=421384237289476&S=1&C=18631",
> "
> http://www.mysite.com/system/empty.asp?P=123&VID=default&SID=421384237289476&S=1&C=18643",
> "
> http://www.mysite.com/system/empty.asp?P=342&VID=default&SID=421384237289476&S=1&C=18634
> ","
> http://www.mysite.com/system/empty.asp?P=232&VID=default&SID=421384237289476&S=1&C=18645",
> "
> http://www.mysite.com/system/empty.asp?P=2345&VID=default&SID=421384237289476&S=1&C=18254",
> "
> http://www.mysite.com/system/empty.asp?P=257654&VID=default&SID=421384237289476&S=1&C=18732",
> "
> http://www.mysite.com/system/empty.asp?P=22&VID=default&SID=421384237289476&S=1&C=18637",
> "
> http://www.mysite.com/system/empty.asp?P=2463&VID=default&SID=421384237289476&S=1&C=18575
> ")
>
> The result should be like
> 2
> 123
> 342
> 232
> 2345
> 257654
> 22
> 2463
>
> Thanks,
> Lauri
>
>        [[alternative HTML version deleted]]
>
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>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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