Re: Position
- To: mathgroup at smc.vnet.net
- Subject: [mg67671] Re: Position
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Tue, 4 Jul 2006 01:57:27 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 7/3/06 at 6:37 AM, vze269bv at verizon.net (Bruce Colletti) wrote:
>Let X be a list of strings having diverse lengths (some are the null
>string "").
>What command returns the position in X of the first element that
>starts with "abcd"?
>Presumably the command looks like Position[X,...,Heads->False], but
>my attempts have come up dry. Although StringTake[Y,4]=="abcd"
>would seem to be part of the command, this fails when the string's
>length is less than 4.
It seems to me, what you want is StringPosition, i.e..
In[3]:=
StringPosition[#,"bc"]&/@{"abd","abcd","","bc"}
In[3]:=
(StringPosition[#1, "bc"] & ) /@ {"abd", "abcd", "", "bc"}
Out[3]=
{{}, {{2, 3}}, {}, {{1, 2}}}
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