Simplest way to get 2 digits from an integer...
in [Mathematica]
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From: Murta on 12 Jul 2010 01:04 Hello All I would like to find a simplest code to take the first n digits os a integer. Here are two examples (not simple) to take the first 2 digits os the number a: 1) a = 1234; ToExpression(a)StringTake[ToString[a], 2] 12 2) a = 1234; FromDigits(a)Take[IntegerDigits[a],2] 12 ------- In Excel, I just use Left(a,2)*1 (multiply by 1 to get a number, instead of text) There is one simplest way in Mathematica!? thanks in advance Rodrigo Murta
From: Peter Breitfeld on 12 Jul 2010 07:22 Murta wrote: > Hello All > > I would like to find a simplest code to take the first n digits os a integer. > Here are two examples (not simple) to take the first 2 digits os the number a: > > 1) > a = 1234; > ToExpression(a)StringTake[ToString[a], 2] > 12 > > 2) > a = 1234; > FromDigits(a)Take[IntegerDigits[a],2] > 12 > ------- > In Excel, I just use Left(a,2)*1 (multiply by 1 to get a number, > instead of text) > There is one simplest way in Mathematica!? > > thanks in advance > Rodrigo Murta > You can use IntegerDigits and FromDigits like this firstN[a_Integer, n_Integer]:=FromDigits(a)IntegerDigits[a][[1;;n]] In= firstN[1234,2] Out=12 -- _________________________________________________________________ Peter Breitfeld, Bad Saulgau, Germany -- http://www.pBreitfeld.de
From: Bill Rowe on 12 Jul 2010 07:21 On 7/12/10 at 1:04 AM, rodrigomurtax(a)gmail.com (Murta) wrote: >Hello All > >I would like to find a simplest code to take the first n digits os a >integer. Here are two examples (not simple) to take the first 2 >digits os the number a: >1) a = 1234; ToExpression(a)StringTake[ToString[a], 2] >12 >2) a = 1234; >FromDigits(a)Take[IntegerDigits[a],2] >12 Simplest is somewhat subjective. Here are two other ways: In[2]:= Floor[10^(1 + FractionalPart[Log[10, a]])] Out[2]= 12 In[3]:= FromDigits[RealDigits[a] /. {a_, _} :> {a[[;; 2]], 2}] Out[3]= 12 This last will return the first two significant digits of any real number regardless of where the decimal point is.
From: Murray Eisenberg on 13 Jul 2010 05:27 You say you want the first two digits, but actually the results you're showing produce an integer having those two digits. Here's a way for both, without resorting to strings at all: n = 49804713; Take[IntegerDigits[n], 2] {4, 9} FromDigits[Take[IntegerDigits[n], 2]] 49 On 7/12/2010 1:04 AM, Murta wrote: > Hello All > > I would like to find a simplest code to take the first n digits os a integer. > Here are two examples (not simple) to take the first 2 digits os the number a: > > 1) > a = 1234; > ToExpression(a)StringTake[ToString[a], 2] > 12 > > 2) > a = 1234; > FromDigits(a)Take[IntegerDigits[a],2] > 12 > ------- > In Excel, I just use Left(a,2)*1 (multiply by 1 to get a number, > instead of text) > There is one simplest way in Mathematica!? > > thanks in advance > Rodrigo Murta > -- Murray Eisenberg murray(a)math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305
From: Matthias Bode on 13 Jul 2010 05:27
Hola: n2 == 95231; IntegerPart[n2/10^IntegerPart[Log[10, n2] - 1]] Simple(st)? Best regards, MATTHIAS BODE COCHABAMBA/BOLIVIA > Date: Mon, 12 Jul 2010 07:22:22 -0400 > From: phbrf(a)t-online.de > Subject: Re: Simplest way to get 2 digits from an integer... > To: mathgroup(a)smc.vnet.net > > Murta wrote: > > > Hello All > > > > I would like to find a simplest code to take the first n digits os a in= teger. > > Here are two examples (not simple) to take the first 2 digits os the nu= mber a: > > > > 1) > > a == 1234; > > ToExpression(a)StringTake[ToString[a], 2] > > 12 > > > > 2) > > a == 1234; > > FromDigits(a)Take[IntegerDigits[a],2] > > 12 > > ------- > > In Excel, I just use Left(a,2)*1 (multiply by 1 to get a number, > > instead of text) > > There is one simplest way in Mathematica!? > > > > thanks in advance > > Rodrigo Murta > > > > You can use IntegerDigits and FromDigits like this > > firstN[a_Integer, n_Integer]:==FromDigits(a)IntegerDigits[a][[1;;n]] > > In== firstN[1234,2] > Out==12 > > -- > _________________________________________________________________ > Peter Breitfeld, Bad Saulgau, Germany -- http://www.pBreitfeld.de > |