Re: Help needed with List!

• To: mathgroup at smc.vnet.net
• Subject: [mg16948] Re: Help needed with List!
• From: "Stephen P Luttrell" <luttrell at signal.dra.hmg.gb>
• Date: Thu, 8 Apr 1999 02:32:45 -0400
• Organization: Defence Evaluation and Research Agency
• References: <7ec5kg\$cu2@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```>Sirs Probably these are FAQs but I am new in this newsgroup and I have not
>been able to solve them. I use Mathematica 3.0:  (i) I need to convert a
long
>integer number in List format. For example if I had the number 123456 I
need
>to convert it into {1,2,3,4,5,6}:  Is it possible with an instruction? And,
>(ii) I need to delete from a List A the common elements with other List B:
>for example if A = {1,2,3,4} and B = {1,2} I need to delete by an
instruction
>the elements 1, 2 of List B from List A to obtain List C = {3,4}.  I am
>working with integers with 10.000 digits or more so you can appreciate how
>helpful for me it would be to solve these questions.  Thanks in advance.
>alvaroo

Here is a solution:

In[1]:=IntegerDigits[123456 ]

Out[1]={1,2,3,4,5,6}

In[2]:=
A = {1,2,3,4} ;
B = {1,2} ;
Select[A,FreeQ[B,#]&]

Out[2]={3,4}

Stephen P Luttrell
Signal Processing and Imagery Department
Malvern, United Kingdom, WR14 3PS

+44 (0)1684 894046 (tel)
+44 (0)1684 894384 (fax)
luttrell at signal.dera.gov.uk (email)

```

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