Re: Length and Drop
- To: mathgroup at smc.vnet.net
- Subject: [mg32199] Re: [mg32183] Length and Drop
- From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
- Date: Sat, 5 Jan 2002 00:10:41 -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?
>
>
>
>