All,
Why does this fail?
irb(main):009:0> sprintf("%d", '08')
ArgumentError: invalid value for Integer: "08"
from (irb):9:in `sprintf'
from (irb):9
I assume it's because the 08 is being as an octal number prior to being
changed to a decimal. 01 - 07 work fine, 09 breaks.
But I'm telling sprintf to interpret it as decimal, so why can't I have
leading zeroes?
Please explain to me how this is expected behavior.
Thanks,
Wes
because:
harp:~ > cat a.c
main(){ char s[42]; int r = sprintf (s, "%d", 07); printf ("%d: <%s>\n", r, s); }
harp:~ > gcc a.c
harp:~ > a.out
1: <7>
harp:~ > cat a.c
main(){ char s[42]; int r = sprintf (s, "%d", 08); printf ("%d: <%s>\n", r, s); }
harp:~ > gcc a.c
a.c: In function `main':
a.c:1: numeric constant contains digits beyond the radix
ruby uses 'Integer(s)' to convert strings to ints and
harp:~ > ri Kernel.Integer
--------------------------------------------------------- Kernel#Integer
Integer(arg) => integer
------------------------------------------------------------------------
Converts _arg_ to a +Fixnum+ or +Bignum+. Numeric types are
converted directly (with floating point numbers being truncated).
If _arg_ is a +String+, leading radix indicators (+0+, +0b+, and
+0x+) are honored. Others are converted using +to_int+ and +to_i+.
This behavior is different from that of +String#to_i+.
Integer(123.999) #=> 123
Integer("0x1a") #=> 26
Integer(Time.new) #=> 1049896590
harp:~ > ruby -e' Integer "07" '
harp:~ > ruby -e' Integer "08" '
-e:1:in `Integer': invalid value for Integer: "08" (ArgumentError)
from -e:1
so it's expected, documented, and consistent with c.
a good pattern to use is:
harp:~ > ruby -e' atoi = lambda{|s| Integer(s) rescue %r/(\d+)/.match(s)[1].to_i rescue raise ArgumentError, s}; p(atoi["08"]); p(atoi["fubar"]) '
8
-e:1: fubar (ArgumentError)
from -e:1
because simply falling back on to_i yields
harp:~ > ruby -e' atoi = lambda{|s| Integer(s) rescue s.to_i}; p(atoi["08"]); p(atoi["fubar"]) '
8
0
regards.
-a
