# BigDecimal

**URL:** <https://www.ruby-forum.com/t/bigdecimal/98666>\
**Category:** Development\
**Created:** [July 17, 2006, 10:57am UTC](https://www.ruby-forum.com/t/bigdecimal/98666 "2006-07-17T10:57:48Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tadayoshi\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/2bfe46/32.png) [@Tadayoshi\_F](https://www.ruby-forum.com/u/Tadayoshi_F)\
**Post date:** [July 17, 2006, 10:57am UTC](https://www.ruby-forum.com/t/bigdecimal/98666/1 "2006-07-17T10:57:48Z")

</div>

e$B$U$J$P$G$9!#e(B

BigDecimal e$B$K$D$$$F;W$C$?$3$H$r$@$i$@$i$H=q$-$^$9!#e(B

e$B$^$:!"e(Brequire ‘bigdecimal/util’  
e$B$9$k$N$,\>/$7LLE]$J$s$G$9$,!“K\BN$HJL$Ke(B  
e$B$9$k0UL#$O$”$k$N$G$7$g$&$+!#!#$^$?!"e(Brequire ‘bigdecimal/util’  
e$B$7$F$b!“e(B  
{BigDecimal,Integer,NilClass}#to\_d e$B$,$”$j$^$;$s!#e(B

e$B5U$K!“e(Bbigdecimal/util.rb e$B$G!“e(BBigDecimal#to\_r  
e$B$rDj5A$7$F$$$k$N$O\>/$7ITe(B  
e$B;W5D$J46$8$b$”$j$^$9!#e(BRational e$B$be(B BigDecimal  
e$B$bBPEy$J4X78$K8+$($k$N$G!“e(B  
Rational  
e$BB&$GDs6!$5$l$F$$$F$b$\*$+$7$/$J$$$H;W$$$^$9!#$3$N$h$&$J\>l9g$Ke(B  
e$B$I$&$9$Y$-$+$N$+!”;X?K$J$I$,$”$l$PCN$j$?$$$G$9!#e(B

[ruby-list:42523]  
e$B$NOC$O$h$/$o$+$i$J$+$C$?$N$G$9$,!"$3$l$K4XO"$7$F!“e(B  
String#to\_d  
e$B$N@:EY$K$D$$$F2]Bj$H$$$&$N$O$”$k$N$G$7$g$&$+!#$"$k$H$9$l$P!"e(B  
e$B2~A1$N2DG=@-$K$D$$$FCN$j$?$$$G$9!#e(B

floore$B!"e(Bceile$B!"e(Btruncatee$B!“e(Bround e$B$NCM$,e(B BigDecimal  
e$B$K$J$j$^$9!#e(Bdivmod e$B$N$Re(B  
e$B$H$DL$NMWAG$b$=$&$G$9!#$3$l$O!“B\>$N?tCM%/%i%9$H0[$J$j$^$9$,!”$3$l$K$De(B  
e$B$$$Fe(BBigDecimal e$BFCM-$NM}M3$,$”$k$N$G$7$g$&$+!#e(B

BigDecimal#div e$B$N7k2L$be(B BigDecimal  
e$B$K$J$j$^$9!#e(BBigDecimal#div e$B$O$U$?$De(B  
e$BL$N\>JN,2DG=$J0z?t$,$"$j!"$3$N$?$a$K!"B\>$N$b$N$H$O0c$&$b$N$K$J$C$F$7$^$Ce(B  
e$B$F$$$k$H;W$$$^$9!#e(B

e$BL58BBg$J$I$re(B to\_i e$B$9$k$He(B nil e$B$K$J$j$^$9$,!“e(BFloat  
e$B$G$ONc30$K$J$j$^$9!#e(B  
e$B$3$N0c$$$KM}M3$O$”$k$N$G$7$g$&$+!#e(B

(1.0/0).to\_i # FloatDomainError  
(1.0/0).to\_d.to\_i #=\> nil

BigDecimal(‘9e’)  
e$B$O%(%i!\<$K$J$k$Y$-$@$H;W$$$^$9!#e(BBigDecimal(’’)e$B!"e(B  
BigDecimal(’\_9’)e$B!"e(BBigDecimal(’–9’)  
e$B$J$I$b%(%i!\<$K$O$J$j$^$;$s!#e(B

BigDecimal(0)e$B!"e(BBigDecimal(0.0)  
e$B$H=q$1$F$b$$$$$h$&$J5$$,$7$^$9!#e(B

ruby 1.9 e$B$G!"e(BBigDecimal(‘1’) == nil  
e$B$,%(%i!\<$K$J$j$^$9!#e(B!=e$B!"e(B===e$B!"e(Beql?  
e$B$bF1$8$G$9!#e(B

bigdecimal/math e$B$K$Oe(B BigMath e$B%b%8%e!\<%k$,$"$j$^$9$,!"\>o$Ke(B  
include  
BigMath e$B$7$F$/$l$H$$$&$3$H$J$N$+!"e(BBigMath::PI(100)  
e$B$N$h$&$K;2\>H$G$-$^e(B  
e$B$;$s!#e(B

e$B$"$H!"e(BRational e$B$H$OJQ49$dHf3S$O=PMh$^$9$,!“e(BaBigDecimal \*  
aRational e$B$Je(B  
e$B$I$,=PMh$^$;$s$,!”$3$l$O$3$&$$$&$b$N$J$s$G$9$+$M!#e(B