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Re: pattern matching

  • To: mathgroup at smc.vnet.net
  • Subject: [mg128317] Re: pattern matching
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Sat, 6 Oct 2012 01:52:12 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • Delivered-to: l-mathgroup@wolfram.com
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On 10/5/12 at 2:52 AM, dnlsnd777 at gmail.com (Daniel Sanders) wrote:

>Consider the following code:

>Count[Table[
>Count[Table[RandomInteger[], {n}], 1]/n, {n, 100, 1000, 10}], x_ <
>.5]

>I want to count the number of times there are occurrences less than
>.5 but some how I am not specifying the right pattern.  Any
>suggestions on getting right?

You need to use PatternTest rather than just a pattern. That is:

In[13]:= MatchQ[.2, x_ < .5]

Out[13]= False

In[14]:= MatchQ[.2 , _?(# < .5 &)]

Out[14]= True




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