# [plt-scheme] Combining digits to form numbers

>* > (foldl (lambda (x y) ( + x (* y 10) )) 0 '(1 2 3))
*>* 123
*
-- Matthias
On Feb 16, 2009, at 8:21 PM, Tim Wawrzynczak wrote:
>* I think you're looking for something like this?
*>*
*>* (foldr (lambda (x y) ( + x (* y 10) )) 0 (reverse '(1 2 3)))
*>* = 123
*>*
*>* - inforichland
*>*
*>* On Mon, Feb 16, 2009 at 7:08 PM, Thomas Chust <chust at web.de> wrote:
*>* 2009-02-16 aditya shukla <adityashukla1983 at gmail.com>:
*>* > [...]
*>* > (define guess (lambda(lsb csb msb)
*>* > This is the part which i was not able to do , how can i
*>* combine lsb
*>* > , csb and msb so the number is of the form (msbcsblsb) .Is there any
*>* > function in scheme which can do this
*>* >
*>* > ))
*>* > [...]
*>*
*>* Hello,
*>*
*>* there are indeed functions in Scheme that can be used do this -- they
*>* are called + and * ;-)
*>*
*>* All you need to do is multiply each digit of the number with the value
*>* of its position and add up the results. If you want to create a more
*>* general solution for an arbitrary number of digits, a function like
*>* foldr comes in handy, too.
*>*
*>* cu,
*>* Thomas
*>*
*>*
*>* --
*>* When C++ is your hammer, every problem looks like your thumb.
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*
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