RE: Pattern Matching in Lists

• To: mathgroup at smc.vnet.net
• Subject: [mg35555] RE: [mg35547] Pattern Matching in Lists
• From: "Florian Jaccard" <jaccardf at eicn.ch>
• Date: Fri, 19 Jul 2002 06:07:55 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Hello !

Here my first try. But there surely exist's a better method !

In[1]:=
w={1,1,1,0,0,1,0,1,0,0,1,0,0};

In[2]:=
f[0]=0;

In[3]:=
Table[If[w[[i]]==1 && w[[i+1]]==0,f[i]=f[i-1]+1,f[i]=f[i-1]],{i,1,
Length[w]}]//Last

Out[3]=
4

Meilleures salutations

Florian Jaccard
EICN-HES
e-mail : jaccardf at eicn.ch

-----Message d'origine-----
De : Anthony Mendes [mailto:amendes at zeno.ucsd.edu]
Envoyé : jeu., 18. juillet 2002 09:07
À : mathgroup at smc.vnet.net
Objet : [mg35547] Pattern Matching in Lists

Hello,

Suppose w={1,1,1,0,0,1,0,1,0,0,1,0,0}.

How can I count the number of occurrences of a 1 in w immediately
followed by a 0 in w?

I have tried every incarnation of Count[] I can think of; for example,

Count[w,{___,1,0,___}]

does not seem to work.  In general, how can I count the number of
occurrences of a 1 followed by a 0 in a list of 1's and 0's?  Thank you!

--
Tony
_____________________
amendes at math.ucsd.edu

```

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