# Time.now + str $B$H(B #to\_r

**URL:** <https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884>\
**Category:** Development\
**Created:** [December 7, 2009, 4:42am UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884 "2009-12-07T04:42:37Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 7, 2009, 4:42am UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/1 "2009-12-07T04:42:37Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

[ruby-core:23729]e$B$G;XE&$5$l$?e(BTimee$B$He(Bstringe$B$N2C;;$,%(%i!\<$K$Je(B  
e$B$i$J$$M}M3$O!"e(B1.9e$B$Ge(BRationale$B$,AH$\_9~$^$l$?$3$H$G!"e(B

- String#to\_re$B$,Ds6!$5$l$?e(B
- 

String#to\_re$B$Oe(BRationale$B$H$7$F2r\<a$G$-$J$$J8;zNs$Ke(B0e$B$rJV$9e(B

- timee$B$,FbIt7W;;$Ke(BRationale$B$r;H$&$h$&$K$J$C$?e(B
- timee$B$,%\*%Z%i%s%I$NJQ49$Ke(Bto\_re$B$r;H$&$h$&$K$J$C$?e(B

e$B$H$$$&%3%s%$K$h$C$FH/@8$7$^$7$?!#$$$A$_$&!"e(BTime#+e$B$N@5Ev$J0ze(B  
e$B?t$H$7$FJ8;zNse(B(T\_STRINGe$B$_$h$Se(Bto\_stre$B$r;}$D%\*%V%8%’%/%He(B)e$B$r30$9e(B  
e$B$H$$$&BP1~$r9T$$$^$7$?$,!"@8\<Q$(46$,$L$0$($^$;$s!#e(B

e$B5$$KF~$i$J$$860x$r2~$a$F9M$($F$\_$^$7$?$,!"$I$&$d$i0J2\<$NJ#9ge(B  
e$B$N$h$&$G$9!#e(B

- 

to\_re$B$H$$$&L\>A0$O$h$/$J$$!#e(Bre$B$,e(Brationale$B$@$+e(Bregexpe$B$@$+e(Brange  
e$B$@$+$o$+$i$J$$!#D9G/$NMxMQ$G$b$&DjCe$7$F$7$^$C$?e(B  
s(string), i(integer), a(array)e$B$O;EJ}$,$J$$$H$7$F$b!"$3$le(B  
e$B0J\>ee(B1e$BJ8;ze(Bto\_?e$B%a%=%C%I$rA}$d$9$Y$-$G$O$J$$!#$3$NE@$G$Oe(B  
BigDecimal#to\_de$B$bF1:ae(B

- 

Timee$B$,e(Bto\_re$B$r;H$C$F$$$k$N$b$h$/$J$$!#L\>A0$,NI$/$J$$$3$H$K2Ce(B  
e$B$($F!"%_%Z%i%s%I$N0EL[$N7?JQ49$N$?$a$Ne(B(to\_inte$B$N$h$&$Je(B)e$B%ae(B  
e$B%=%C%I$O!"L@\<(E_$J7?JQ49$r9T$&e(B(to\_ie$B$N$h$&$Je(B)e$B%a%=%C%I$HJ,e(B  
e$BN%$5$l$F$$$k$Y$-$G$"$m$&!#e(B

- e$B$7$+$7!“e(BRationale$B$O8=\>u$=$N$h$&$J%a%=%C%I$rDs6!$7$F$$$J$$e(B  
(e$B\<BAu$O$”$ke(B)e$B!#e(B

- 

e$B$=$b$=$be(Bto\_ie$B$He(Bto\_inte$B$N$h$&$J!“L@\<(E\*$JJQ49$H0EL[E\*$JJQ49$Ne(B  
e$B%Z%”$N$?$a$NE}0lE\*$J%M!\<%\_%s%0%k!\<%k$,$J$$!#e(B

e$B$H$$$&$3$H$G!"\<j85$G0J2\<$N$h$&$JJQ99$r9T$&e(B(e$B$+$J$jBg$-$a$Ne(B)e$B%Q%Ce(B  
e$B%A$r:n$C$F$\_$^$7$?$,!"$3$l$G$bK~B-$G$-$^$;$s!#e(B

- to\_re$B$He(Bto\_de$B$r:o=|e(B
- e$BL@\<(E\*$JJQ49$Oe(Bas\_xxxe$B!"0EL[E\*$JJQ49$Oe(Bto\_xxx
- to\_ie$B$J$I$K$Oe(Bas\_inte$B$H$$$&JLL\>e(B
- e$B4pK\E\*%/%i%9e(B(int,str,ary)e$B0J30$O%U%k%M!\<%`e(B.to\_lower
- e$B$h$C$Fe(BTimee$B$NJQ49$K$Oe(Bto\_rationale$B$r;H$&e(B

e$B$3$N%Q%C%A$N:GBg$N\<eE@$O:n$C$?K?M$be(Btoe$B$He(Base$B$,$I$C$A$,$I$C$A$@e(B  
e$B$+K:$l$F$7$^$&$H$$$&$H$3$m$G$7$g$&!#$^$?!“JQ99$N5,LO$,Bg$-$$e(B  
e$B$N$Ge(B1.9.2e$B$K$O\<jCY$l$H$$$&46$b$”$j$^$9!#;d$H$7$F$Oe(Bto\_re$B$de(Bto\_de$B$,e(B  
e$B$3$l0J\>e9-$^$i$J$$$&$A$K\<j$rBG$A$?$$$N$G$9$,!"$=$N$X$s$Oe(B  
Yuguie$B$5$s$NH=CG$KG$$;$k$H$7$F!#e(B

e$B$G!“L@\<(E\*$JJQ49$H0EL[E\*$JJQ49$N$?$a$NL?L\>86B’$O$I$N$h$&$J$be(B  
e$B$N$,$h$$$N$+!”$H$$$&E@$K$D$$$F!"$$$m$$$m$H$40U8+$rJ9$+$;$F$/e(B  
e$B$@$5$$$^$;!#$"$k$$$O\>e5-LdBj$N$^$C$?$/JL$N2r7hJ}K!$,;W$$$D$$e(B  
e$B$?\>l9g$K$O!"$=$l$bJ9$-$?$$$G$9!#?t$NAj8\_7?JQ49$r9T$&$h$&$J%7e(B  
e$B%9%F%`$N9=C[$H$$$&2r$b$"$j$($k$+$b$7$l$^$;$s!#e(B

e$B$"$H!"8=\>u$G$OL@\<(E\*$JJQ49$NJ}$Oe(B

“foo”.to\_i # =\> 0

e$B$N$h$&$J!"$o$j$H%+%8%e%"%k$JJQ49$r$7$F$$$^$9$,!"$3$l$O$&$l$7e(B  
e$B$$$3$H$,\>/$J$$$N$G!":#8e?7$?$KDI2C$9$k\>l9g$Oe(B(Raional e$B$b4^$ae(B  
e$B$Fe(B)e$B!"%(%i!\<$r$"$2$k$Y$-$G$O$J$$$+$H;W$&$h$&$K$J$j$^$7$?$,!"$3e(B  
e$B$l$O$^$?JL$NOC$H$7$F5DO@$9$Y$-$G$7$g$&!#e(B

```
                            e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)
```

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 7, 2009, 6:36am UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/2 "2009-12-07T06:36:44Z")

</div>

e$B@.@%$G$9!#e(B

2009/12/07 12:42, Yukihiro M. wrote:

> - e$B4pK\E\*%/%i%9e(B(int,str,ary)e$B0J30$O%U%k%M!\<%`e(B.to\_lower

FooBar e$B%/%i%9$N\>l9g$O!"e(Bto\_foobar e$B$G$9$+!"e(B to\_foo\_bar  
e$B$G$9$+e(B

> e$B$3$N%Q%C%A$N:GBg$N\<eE@$O:n$C$?K?M$be(Btoe$B$He(Base$B$,$I$C$A$,$I$C$A$@e(B  
> e$B$+K:$l$F$7$^$&$H$$$&$H$3$m$G$7$g$&!#$^$?!“JQ99$N5,LO$,Bg$-$$e(B  
> e$B$N$Ge(B1.9.2e$B$K$O\<jCY$l$H$$$&46$b$”$j$^$9!#;d$H$7$F$Oe(Bto\_re$B$de(Bto\_de$B$,e(B  
> e$B$3$l0J\>e9-$^$i$J$$$&$A$K\<j$rBG$A$?$$$N$G$9$,!"$=$N$X$s$Oe(B  
> Yuguie$B$5$s$NH=CG$KG$$;$k$H$7$F!#e(B

1.9.2 e$B$N%j%j!\<%9$Oe(B 2010 e$BG/e(B 6 e$B7n:“$@$H;W$C$F$$$k$N$G!“e(B  
e$BM1M=$O$^$@$”$k$+$J$!$H;W$C$F$$$^$9$,!”$^$!e(B Yugui  
e$B$5$sH=CG$G$9$M!#e(B

> e$B$“$k$$$O\>e5-LdBj$N$^$C$?$/JL$N2r7hJ}K!$,;W$$$D$$e(B  
> e$B$?\>l9g$K$O!”$=$l$bJ9$-$?$$$G$9!#?t$NAj8\_7?JQ49$r9T$&$h$&$J%7e(B  
> e$B%9%F%`$N9=C[$H$$$&2r$b$"$j$($k$+$b$7$l$^$;$s!#e(B

- String e$B$rL@\<(E\*$Ke(B Rational e$B$KJQ49$9$k%a%=%C%I$O$"$C$F$h$$e(B
- String e$B$r0EL[E\*$Ke(B Rational  
e$B$KJQ49$9$k%a%=%C%I$O$"$C$F$O$J$i$J$$e(B
- Time e$B$rL@\<(E\*!&0EL[E\*$Ke(B Rational  
e$B$KJQ49$9$k%a%=%C%I$O$“$C$F$h$$e(B  
e$B$H;W$&$N$G!”$\*$J$82r7h:v$K$J$k$h$&$K;W$$$^$9!#e(B

> e$B$G!“L@\<(E\*$JJQ49$H0EL[E\*$JJQ49$N$?$a$NL?L\>86B’$O$I$N$h$&$J$be(B  
> e$B$N$,$h$$$N$+!”$H$$$&E@$K$D$$$F!"$$$m$$$m$H$40U8+$rJ9$+$;$F$/e(B  
> e$B$@$5$$$^$;!#e(B

e$B0EL[E_JQ49$,e(B to\_xxx  
e$B$G$“$k!”$H$$$&$3$H$,!"8\_49@-E_$KF0$+$;$J$$0J\>e!"e(B  
e$BL@\<(E_JQ49$r$$$+$K$b!VL@\<(E_!W$J%a%=%C%I$K$7$?J}$,$h$$$h$&$K;W$&$H$3$m!“e(B  
as\_xxx e$B$H$$$&$N$O$A$g$C$H\<e$$$s$8$c$J$$$G$7$g$&$+!#e(B  
convert\_xxx e$B$H$+e(B cast\_xxx  
e$B$H$+!”$b$C$H$$$+$K$b$J%a%=%C%IL\>$N$[$&$,e(B  
e$B$$$$$h$&$K46$8$^$9!#e(B

> e$B$"$H!"8=\>u$G$OL@\<(E\*$JJQ49$NJ}$Oe(B
> 
> “foo”.to\_i # =\> 0
> 
> e$B$N$h$&$J!“$o$j$H%+%8%e%”%k$JJQ49$r$7$F$$$^$9$,!“$3$l$O$&$l$7e(B  
> e$B$$$3$H$,\>/$J$$$N$G!”:#8e?7$?$KDI2C$9$k\>l9g$Oe(B(Raional e$B$b4^$ae(B  
> e$B$Fe(B)e$B!“%(%i!\<$r$”$2$k$Y$-$G$O$J$$$+$H;W$&$h$&$K$J$j$^$7$?$,!"$3e(B  
> e$B$l$O$^$?JL$NOC$H$7$F5DO@$9$Y$-$G$7$g$&!#e(B

String#to\_i / NilClass#to\_i e$B$K4X$7$F$O$?$^$K;H$$$^$9!#e(B  
[Xi Bot for nadoka · GitHub](http://gist.github.com/213354) e$BNc$($P$3$le(B  
e$B30$+$iMh$?F~NO$r?tCM$KJQ49$7$?\>e$GCM0h$r8+$?$$\>l9g$K;H$C$F$$$^$9!#e(B  
e$B$b$C$H$b!“$3$l$Oe(B NilClass#to\_i  
e$B$,$”$k$H$$$&FC\<l@-$+$iMh$F$$$k$N$G!“e(B  
e$B$3$l$+$i30$l$k$b$N$K$O$”$?$i$J$$$+$b$7$l$^$;$s$,!#e(B

# NilClass#to\_r e$B$O8=:_B8:_$9$ke(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 14, 2009, 1:03am UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/3 "2009-12-14T01:03:17Z")

</div>

e$B$`$i$?$G$9!#e(B

On 2009/12/07, at 14:36, NARUSE, Yui wrote:

> > e$B$G!“L@\<(E\*$JJQ49$H0EL[E\*$JJQ49$N$?$a$NL?L\>86B’$O$I$N$h$&$J$be(B  
> > e$B$N$,$h$$$N$+!”$H$$$&E@$K$D$$$F!"$$$m$$$m$H$40U8+$rJ9$+$;$F$/e(B  
> > e$B$@$5$$$^$;!#e(B
> 
> e$B0EL[E_JQ49$,e(B to\_xxx e$B$G$“$k!”$H$$$&$3$H$,!"8\_49@-E_$KF0$+$;$J$$0J\>e!"e(B  
> e$BL@\<(E_JQ49$r$$$+$K$b!VL@\<(E_!W$J%a%=%C%I$K$7$?J}$,$h$$$h$&$K;W$&$H$3$m!“e(B  
> as\_xxx e$B$H$$$&$N$O$A$g$C$H\<e$$$s$8$c$J$$$G$7$g$&$+!#e(B  
> convert\_xxx e$B$H$+e(B cast\_xxx e$B$H$+!”$b$C$H$$$+$K$b$J%a%=%C%IL\>$N$[$&$,e(B  
> e$B$$$$$h$&$K46$8$^$9!#e(B

convert\_to(Rational) e$B$H$+e(B cast\_to(Rational) e$B$N$h$&$K!"e(B  
e$BJQ49@h$N%/%i%9$r0z?t$H$7$FM?$($kJ}K!$OG!2?$G$7$g$&!)e(B

–  
Kenta M.  
OpenPGP FP = FA26 35D7 4F98 3498 0810 E0D5 F213 966F E9EB 0BCC

e$BK$r=q$-$^$7$?e(B!!  
e$B!Xe(BRuby e$B5U0z$-%l%7%T!Ye(B

> **[Ruby 逆引きレシピ すぐに美味しいサンプル&amp;テクニック 232 (PROGRAMMER’S RECIPE) | 島田 浩二, 設樂 洋爾, 村田...](https://www.amazon.co.jp/%E9%80%86%E5%BC%95%E3%81%8D%E3%83%AC%E3%82%B7%E3%83%94-%E3%81%99%E3%81%90%E3%81%AB%E7%BE%8E%E5%91%B3%E3%81%97%E3%81%84%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB-%E3%83%86%E3%82%AF%E3%83%8B%E3%83%83%E3%82%AF-PROGRAMMER%E2%80%99S-RECIPE/dp/4798119881)**
>
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E-mail: removed\_email\_address@domain.invalid  
twitter: [http://twitter.com/mrkn/](http://twitter.com/mrkn/)  
blog: [ドレッシングのような](http://d.hatena.ne.jp/mrkn/)

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 25, 2009, 3:42pm UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/4 "2009-12-25T15:42:05Z")

</div>

2009e$BG/e(B12e$B7ne(B7e$BF|e(B12:42 Yukihiro M.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> e$B$3$N%Q%C%A$N:GBg$N\<eE@$O:n$C$?K?M$be(Btoe$B$He(Base$B$,$I$C$A$,$I$C$A$@e(B  
> e$B$+K:$l$F$7$^$&$H$$$&$H$3$m$G$7$g$&!#$^$?!“JQ99$N5,LO$,Bg$-$$e(B  
> e$B$N$Ge(B1.9.2e$B$K$O\<jCY$l$H$$$&46$b$”$j$^$9!#;d$H$7$F$Oe(Bto\_re$B$de(Bto\_de$B$,e(B  
> e$B$3$l0J\>e9-$^$i$J$$$&$A$K\<j$rBG$A$?$$$N$G$9$,!"$=$N$X$s$Oe(B  
> Yuguie$B$5$s$NH=CG$KG$$;$k$H$7$F!#e(B

to e$B$He(B as e$B$,F1$8D9$5$J$N$,$h$m$7$/$J$$$N$G$O$J$$$G$9$+$M$'!#e(B

intern\_to\_rational e$B$H$+!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 16, 2009, 5:41pm UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/5 "2009-12-16T17:41:55Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:39877] Re: Time.now + str e$B$He(B #to\_r”  
on Mon, 14 Dec 2009 09:02:24 +0900, Kenta M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|convert\_to(Rational) e$B$H$+e(B cast\_to(Rational) e$B$N$h$&$K!"e(B  
|e$BJQ49@h$N%/%i%9$r0z?t$H$7$FM?$($kJ}K!$OG!2?$G$7$g$&!)e(B

e$B$=$N\>l9g!“e(Bconvert\_toe$B$H$+e(Bcast\_toe$B$H$+$N%a%=%C%I$N\<BAu$NCf$G!”%/e(B  
e$B%i%9$4$H$K\>r7oJ,4t$9$k$N$G$“$l$P!”?7$?$K?t%/%i%9$,A}$($?\>l9ge(B  
e$B$KBP1~$9$k$N$,Fq$7$/$J$k$N$G$O$J$$$G$7$g$&$+!#\<BAu$H$7$F%@%Ve(B  
e$B%k%G%#%9%Q%C%A$r;H$($P!“7k6I$O$J$s$i$+$N%a%=%C%IL\>$r9M$($kI,e(B  
e$BMW$,$”$k$N$G$O$J$$$+$H!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 25, 2009, 4:28pm UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/6 "2009-12-25T16:28:27Z")

</div>

e$B$`$i$?$G$9!#e(B

On 2009/12/17, at 1:41, Yukihiro M. wrote:

> e$B$KBP1~$9$k$N$,Fq$7$/$J$k$N$G$O$J$$$G$7$g$&$+!#\<BAu$H$7$F%@%Ve(B  
> e$B%k%G%#%9%Q%C%A$r;H$($P!“7k6I$O$J$s$i$+$N%a%=%C%IL\>$r9M$($kI,e(B  
> e$BMW$,$”$k$N$G$O$J$$$+$H!#e(B

e$B\<+J,$,CN$i$J$$%/%i%9$X$NJQ49;~$K%@%V%k%G%#%9%Q%C%A$G8F$S=P$9%/%i%9%a%=%C%I$re(B  
convert\_from  
e$B$H$$$&L\>A0$K7h$a$l$P!"$3$N\>l9g$K$D$$$F$OBP\>NE\*$K$J$C$FH~$7$$$H;W$$$^$9!#e(B

–  
Kenta M.  
OpenPGP FP = FA26 35D7 4F98 3498 0810 E0D5 F213 966F E9EB 0BCC

e$BK$r=q$-$^$7$?e(B!!  
e$B!Xe(BRuby e$B5U0z$-%l%7%T!Ye(B

> **[Ruby 逆引きレシピ すぐに美味しいサンプル&amp;テクニック 232 (PROGRAMMER’S RECIPE) | 島田 浩二, 設樂 洋爾, 村田...](https://www.amazon.co.jp/%E9%80%86%E5%BC%95%E3%81%8D%E3%83%AC%E3%82%B7%E3%83%94-%E3%81%99%E3%81%90%E3%81%AB%E7%BE%8E%E5%91%B3%E3%81%97%E3%81%84%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB-%E3%83%86%E3%82%AF%E3%83%8B%E3%83%83%E3%82%AF-PROGRAMMER%E2%80%99S-RECIPE/dp/4798119881)**
>
> Amazonで島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威のRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)。アマゾンならポイント還元本が多数。島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威作品ほか、お急ぎ便対象商品は当日お届けも可能。またRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)もアマゾン配送商品なら通常配送無料。

E-mail: removed\_email\_address@domain.invalid  
twitter: [http://twitter.com/mrkn/](http://twitter.com/mrkn/)  
blog: [ドレッシングのような](http://d.hatena.ne.jp/mrkn/)

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 25, 2009, 5:00pm UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/7 "2009-12-25T17:00:10Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:39915] Re: Time.now + str e$B$He(B #to\_r”  
on Thu, 24 Dec 2009 09:06:06 +0900, Kenta M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|\> e$B$=$N\>l9g!“e(Bconvert\_toe$B$H$+e(Bcast\_toe$B$H$+$N%a%=%C%I$N\<BAu$NCf$G!”%/e(B  
|\> e$B%i%9$4$H$K\>r7oJ,4t$9$k$N$G$“$l$P!”?7$?$K?t%/%i%9$,A}$($?\>l9ge(B  
|\> e$B$KBP1~$9$k$N$,Fq$7$/$J$k$N$G$O$J$$$G$7$g$&$+!#\<BAu$H$7$F%@%Ve(B  
|\> e$B%k%G%#%9%Q%C%A$r;H$($P!“7k6I$O$J$s$i$+$N%a%=%C%IL\>$r9M$($kI,e(B  
|\> e$BMW$,$”$k$N$G$O$J$$$+$H!#e(B  
|  
|e$B\<+J,$,CN$i$J$$%/%i%9$X$NJQ49;~$K%@%V%k%G%#%9%Q%C%A$G8F$S=P$9%/%i%9%a%=%C%I$re(B  
|convert\_from e$B$H$$$&L\>A0$K7h$a$l$P!"$3$N\>l9g$K$D$$$F$OBP\>NE\*$K$J$C$FH~$7$$$H;W$$$^$9!#e(B

e$B$J$s$H$J$/M}2r$G$-$?5$$,$7$J$$$N$G!"$b$&$A$g$C$H@bL@$7$F$b$ie(B  
e$B$($^$;$s$+!#e(B

e$B2\>$Ke(BRationale$B$H$$$&AH$_9~$_$G$J$$%/%i%9$,$"$C$?$H$7$F!"e(B

r = 2.convert\_to(Rational)

e$B$O6qBNE\*$K$O$I$s$J=hM}$r$9$k$N$G$7$g$&!)e(B  
e$B$?$@$7!"e(BRationale$B$OAHe(B  
e$B$_9~$_$G$O$J$$$N$G!"e(B2e$B$Oe(BRationale$B$H$$$&%/%i%9$K$D$$$FCN$i$J$$$3e(B  
e$B$H$H$7$^$9!#e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 25, 2009, 6:43pm UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/8 "2009-12-25T18:43:28Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:39925] Re: Time.now + str e$B$He(B #to\_r”  
on Thu, 24 Dec 2009 20:26:49 +0900, Kenta M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|def convert\_to(target\_klass)  
| case target\_klass  
| when e$BCN$C$F$k%/%i%9e(B1  
| e$BJQ49=hM}e(B1  
| when e$BCN$C$F$k%/%i%9e(B2  
| e$BJQ49=hM}e(B2  
| when …  
| …  
| else  
| target\_klass.convert\_from(self)  
| end  
|end  
|  
|e$B$3$s$J%a%=%C%I$rA[Dj$7$F$$$^$7$?!#e(B

e$B$3$N$d$jJ}$@$HMF0W$KL58B%k!\<%W$KMn$A$^$;$s!)e(B

---

<div class="post-metadata">

**Author:** ![Yukihiro\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/c57346/32.png) [@Yukihiro\_M](https://www.ruby-forum.com/u/Yukihiro_M)\
**Post date:** [December 25, 2009, 5:47pm UTC](https://www.ruby-forum.com/t/time-now-str-b-h-b-to-r/179884/9 "2009-12-25T17:47:13Z")

</div>

e$B$`$i$?$G$9!#e(B

On 2009/12/24, at 9:28, Yukihiro M. wrote:

> |convert\_from e$B$H$$$&L\>A0$K7h$a$l$P!"$3$N\>l9g$K$D$$$F$OBP\>NE\*$K$J$C$FH~$7$$$H;W$$$^$9!#e(B  
> e$B$H$H$7$^$9!#e(B

def convert\_to(target\_klass)  
case target\_klass  
when e$BCN$C$F$k%/%i%9e(B1  
e$BJQ49=hM}e(B1  
when e$BCN$C$F$k%/%i%9e(B2  
e$BJQ49=hM}e(B2  
when …  
…  
else  
target\_klass.convert\_from(self)  
end  
end

e$B$3$s$J%a%=%C%I$rA[Dj$7$F$$$^$7$?!#e(B

–  
Kenta M.  
OpenPGP FP = FA26 35D7 4F98 3498 0810 E0D5 F213 966F E9EB 0BCC

e$BK$r=q$-$^$7$?e(B!!  
e$B!Xe(BRuby e$B5U0z$-%l%7%T!Ye(B

> **[Ruby 逆引きレシピ すぐに美味しいサンプル&amp;テクニック 232 (PROGRAMMER’S RECIPE) | 島田 浩二, 設樂 洋爾, 村田...](https://www.amazon.co.jp/%E9%80%86%E5%BC%95%E3%81%8D%E3%83%AC%E3%82%B7%E3%83%94-%E3%81%99%E3%81%90%E3%81%AB%E7%BE%8E%E5%91%B3%E3%81%97%E3%81%84%E3%82%B5%E3%83%B3%E3%83%97%E3%83%AB-%E3%83%86%E3%82%AF%E3%83%8B%E3%83%83%E3%82%AF-PROGRAMMER%E2%80%99S-RECIPE/dp/4798119881)**
>
> Amazonで島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威のRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)。アマゾンならポイント還元本が多数。島田 浩二, 設樂 洋爾, 村田 賢太, 前田 智樹, 谷口 文威作品ほか、お急ぎ便対象商品は当日お届けも可能。またRuby 逆引きレシピ すぐに美味しいサンプル&テクニック 232 (PROGRAMMER’S RECIPE)もアマゾン配送商品なら通常配送無料。

E-mail: removed\_email\_address@domain.invalid  
twitter: [http://twitter.com/mrkn/](http://twitter.com/mrkn/)  
blog: [ドレッシングのような](http://d.hatena.ne.jp/mrkn/)