R help - Nov 2010 - Create new string of same length as entry in dataframe

I suspect that this is simple, but thanks in advance for any advice...

I have a dataframe, t2:

V1          V2
aaa         3
aaaa       4
aaaaaa    6
a            1
aa          2


V2 is the length of the string in V1 using  nchar(as.character(t1$V1))

I'd like to create a third column, that contains a string of the length of
V2, but containing an alternate text, e.g.

V1          V2     V3
aaa         3      bbb
aaaa       4      bbbb
aaaaaa    6     bbbbbb
a            1     b
aa          2      bb

or

V1          V2    V3
aaa         3     bad
aaaa       4     badb
aaaaaa    6     badbad
a            1     b
aa          2     ba  


Suggestions would be much appreciated!

Thanks.


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Suppose you want to replace using all b's:
> thestring = 'bbbbbbbbbbbbbbbbbbbbbbbbbb'
> t2$V3 = substring(thestring,1,t2$V2)
> t2$V3
[1] "bbb"    "bbbb"   "bbbbbb" "b"     
"bb"

For the second case,
> thestring = paste(rep('bad',5),collapse='')
> thestring
[1] "badbadbadbadbad"
> t2$V3 = substring(thestring,1,t2$V2)
> t2$V3
[1] "bad"    "badb"   "badbad" "b"     
"ba"

Hope this helps.
 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu



On Wed, 24 Nov 2010, danobolg321 wrote:
>
> I suspect that this is simple, but thanks in advance for any advice...
>
> I have a dataframe, t2:
>
> V1          V2
> aaa         3
> aaaa       4
> aaaaaa    6
> a            1
> aa          2
>
>
> V2 is the length of the string in V1 using  nchar(as.character(t1$V1))
>
> I'd like to create a third column, that contains a string of the length
of
> V2, but containing an alternate text, e.g.
>
> V1          V2     V3
> aaa         3      bbb
> aaaa       4      bbbb
> aaaaaa    6     bbbbbb
> a            1     b
> aa          2      bb
>
> or
>
> V1          V2    V3
> aaa         3     bad
> aaaa       4     badb
> aaaaaa    6     badbad
> a            1     b
> aa          2     ba
>
>
> Suggestions would be much appreciated!
>
> Thanks.
>
>
> -- 
> View this message in context:
http://r.789695.n4.nabble.com/Create-new-string-of-same-length-as-entry-in-dataframe-tp3058232p3058232.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Simple, but was taking me a long time to google. 

Thanks Phil, happy Thanksgiving.

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