R help - Mar 2007 - "digits" doesn't work in format function

Dear All,

I was trying to format a numeric vector (100*1) by using
outd <- format(x=m, sci=F, digits=2)
> outd[1:10]
 [1] " 0.01787758" "-0.14760306" "-0.45806041"
"-0.67858525" "-0.64591748"
 [6] "-0.05918100" "-0.25632276" "-0.15980138"
"-0.08359873" "-0.37866688"
>m[1:10]
 [1]  0.017878 -0.147603 -0.458060 -0.678585 -0.645917 -0.059181 -0.256323
 [8] -0.159801 -0.083599 -0.378667

I'm expecting something like, 0.02 -0.15 ...

Any advice how to fix it will be highly appreciated!

Best,
 Baoqiang

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Try

sprintf("%.2f", m)


On 3/22/07, Baoqiang Cao <bqcaomail at gmail.com>
wrote:
> Dear All,
>
> I was trying to format a numeric vector (100*1) by using
> outd <- format(x=m, sci=F, digits=2)
>
> > outd[1:10]
>  [1] " 0.01787758" "-0.14760306"
"-0.45806041" "-0.67858525" "-0.64591748"
>  [6] "-0.05918100" "-0.25632276"
"-0.15980138" "-0.08359873" "-0.37866688"
> >m[1:10]
>  [1]  0.017878 -0.147603 -0.458060 -0.678585 -0.645917 -0.059181 -0.256323
>  [8] -0.159801 -0.083599 -0.378667
>
> I'm expecting something like, 0.02 -0.15 ...
>

On Thu, 2007-03-22 at 09:59 -0500, Baoqiang Cao wrote:
> Dear All,
> 
> I was trying to format a numeric vector (100*1) by using
> outd <- format(x=m, sci=F, digits=2)
> 
> > outd[1:10]
>  [1] " 0.01787758" "-0.14760306"
"-0.45806041" "-0.67858525" "-0.64591748"
>  [6] "-0.05918100" "-0.25632276"
"-0.15980138" "-0.08359873" "-0.37866688"
> >m[1:10]
>  [1]  0.017878 -0.147603 -0.458060 -0.678585 -0.645917 -0.059181 -0.256323
>  [8] -0.159801 -0.083599 -0.378667
> 
> I'm expecting something like, 0.02 -0.15 ...
> 
> Any advice how to fix it will be highly appreciated!
> 
> Best,
>  Baoqiang
The digits argument pertains to the number of _significant digits_. 
>From ?format:
how many significant digits are to be used for numeric and complex x.
The default, NULL, uses getOption(digits). This is a suggestion: enough
decimal places will be used so that the smallest (in magnitude) number
has this many significant digits, and also to satisfy nsmall. (For the
interpretation for complex numbers see signif.)


If you want tight and consistent control over the number of digits after
the decimal place, you would need to use ?sprintf or ?formatC:
> sprintf("%.2f", m)
 [1] "0.02"  "-0.15" "-0.46" "-0.68"
"-0.65" "-0.06" "-0.26" "-0.16"
 [9] "-0.08" "-0.38"

> formatC(m, format = "f", digits = 2)
 [1] "0.02"  "-0.15" "-0.46" "-0.68"
"-0.65" "-0.06" "-0.26" "-0.16"
 [9] "-0.08" "-0.38"


HTH,

Marc Schwartz

FYI,
I got wonderful help from Gabor, Zhuanshi, and Marc, either way of the
following works:

sprintf("%.2f", m)
formatC(x=m, format="f", digits=2)

Thanks you guys!

Best,
 Baoqiang


On 3/22/07, Baoqiang Cao <bqcaomail@gmail.com>
wrote:
>
> Dear All,
>
> I was trying to format a numeric vector (100*1) by using
> outd <- format(x=m, sci=F, digits=2)
>
> > outd[1:10]
>  [1] " 0.01787758" "-0.14760306"
"-0.45806041" "- 0.67858525" "-0.64591748
> "
>  [6] "-0.05918100" "-0.25632276"
"-0.15980138" "-0.08359873" "-0.37866688"
> >m[1:10]
>  [1]  0.017878 -0.147603 -0.458060 -0.678585 -0.645917 -0.059181 -0.256323
>  [8] -0.159801 -0.083599 -0.378667
>
> I'm expecting something like, 0.02 -0.15 ...
>
> Any advice how to fix it will be highly appreciated!
>
> Best,
>  Baoqiang
>
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