Re: Length and Drop

*To*: mathgroup at smc.vnet.net*Subject*: [mg32198] Re: [mg32183] Length and Drop*From*: Andrzej Kozlowski <andrzej at tuins.ac.jp>*Date*: Sat, 5 Jan 2002 00:10:39 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Drop does not affect the original list, it constructs a new one. Your timexp remains unchanged: In[23]:= timexp={{0,0},{7,8}} Out[23]= {{0,0},{7,8}} In[24]:= Drop[timexp,1];timexp Out[24]= {{0,0},{7,8}} Use In[25]:= timexp=Drop[timexp,1];timexp Out[25]= {{7,8}} Andrzej Kozlowski Toyama International University JAPAN http://platon.c.u-tokyo.ac.jp/andrzej/ On Friday, January 4, 2002, at 07:03 PM, Steve Gray wrote: > The following sequence seems wrong to me, in that > after dropping some elements from a list, its Length is > still the same. I copied this directly from the notebook > but removed the In[] and Out[] statements. > > > timexp={{0,0}} -> {{0,0}} [this is ok] > > timexp=Append[timexp,{7,8}] -> {{0,0},{7,8}} [this is ok] > > Length[timexp] -> 2 [this is ok] > > Drop[timexp,1] -> {{7,8}} [this is ok] > > Length[timexp] -> 2 [ this is what I did not expect!] > > Should not Drop reduce the Length of the list by the amount > dropped? > > > >