如何使用整数中的前导零-Howtoworkwithleadingzerosinintegers

10  

A numeric literal that starts with 0 is an octal representation, except the literals that start with 0x which represent hexadecimal numbers or 0b which represent binary numbers.

以0开头的数字文字是八进制表示形式,除了以0x开头的文字表示十六进制数字或0b表示二进制数字。

1 * 8**2 + 1 * 8**1 + 2 * 8**0 == 74

To convert it to 0112, use String#% or Kernel#sprintf with an appropriate format string:

要将其转换为0112,请使用带有适当格式字符串的String#%或Kernel#sprintf:

'0%o' % 0112  # 0: leading zero, %o: represent as an octal
# => "0112"

3  

You can't, because Ruby's Integer class does not store leading zeros.

你不能,因为Ruby的Integer类不存储前导零。

A leading 0 in a number literal is interpreted as a prefix:

数字文字中的前导0被解释为前缀:

• 0 and 0o: octal number

0和0o:八进制数

• 0x: hexadecimal number

0x:十六进制数

• 0b: binary number

0b:二进制数

• 0d: decimal number

0d:十进制数

It allows you to enter numbers in these bases. Ruby's parser converts the literals to the appropriate Integer instances. The prefix or leading zeros are discarded.

它允许您在这些基础中输入数字。 Ruby的解析器将文字转换为适当的Integer实例。前缀或前导零被丢弃。

Another example is %w for entering arrays:

另一个例子是输入数组的%w:

ary = %w(foo bar baz)
#=> ["foo", "bar", "baz"]

There's no way to get that %w from ary. The parser turns the literal into an array instance, so the script never sees the literal.

没有办法从ary获得%w。解析器将文字转换为数组实例,因此脚本永远不会看到文字。

0112 (or 0o112) is interpreted (by the parser) as the octal number 112 and turned into the integer 74.

0112(或0o112)被解析器(由解析器)解释为八进制数112并且变为整数74。

A decimal 0112 is just 112, no matter how many zeros you put in front:

小数0112只有112,无论你放在前面有多少个零:

0d0112   #=> 112
0d00112  #=> 112
0d000112 #=> 112

It's like additional trailing zeros for floats:

这就像花车的额外尾随零:

1.0   #=> 1.0
1.00  #=> 1.0
1.000 #=> 1.0

You probably have to use a string, i.e. "0112"

您可能必须使用字符串,即“0112”

Another option is to provide the (minimum) width explicitly, e.g.:

另一种选择是明确地提供(最小)宽度,例如:

def descending_order(number, width = 0)
  sprintf('%0*d', width, number).reverse.to_i
end

descending_order(123, 4)
#=> 3210

descending_order(123, 10)
#=> 3210000000