Re: Iterate through a list
- To: mathgroup at smc.vnet.net
- Subject: [mg76948] Re: Iterate through a list
- From: Donald DuBois <dfd01 at comcast.net>
- Date: Wed, 30 May 2007 05:30:31 -0400 (EDT)
You can pull out the first member of each sublist
and count the number of occurences of each element
by doing the following:
In[27]:= lst = {{1, 0}, {1, 1}, {2, x + x^2 + x^4}, {2,
1 + x + x^2 + x^4}, {4, x + x^2}}
Out[27]= {{1, 0}, {1, 1}, {2, x + x^2 + x^4}, {2,
1 + x + x^2 + x^4}, {4, x + x^2}}
In[29]:= lst[[All, 1]]
Out[29]= {1, 1, 2, 2, 4}
In[30]:= Tally[%]
Out[30]= {{1, 2}, {2, 2}, {4, 1}}
Hope this helps.
Don