ruby - 将字符串数字（以 word 格式）转换为整数 ruby

Question

如果你有一个字符串ten，是否可以10在 Ruby 中将其转换为整数？（也许在铁轨上？）

我重视 tryruby.org 的开发人员，并且在他们的教程中，它特别说“to_i 将事物转换为整数（数字。）”我想知道为什么他们没有说“to_i 将字符串转换为整数（数字。）”

哪些变量类型可以从它们的类型转换为整数？

Answer 1

查看此 gem以处理单词到数字的转换。

从自述文件：

require 'numbers_in_words'
require 'numbers_in_words/duck_punch'

112.in_words
#=> one hundred and twelve
"Seventy million, five-hundred and fifty six thousand point eight nine three".in_numbers
#=> 70556000.893

Answer 2

我会怎么做。

def n_to_s(int)

    set1 = ["","one","two","three","four","five","six","seven",
         "eight","nine","ten","eleven","twelve","thirteen",
         "fourteen","fifteen","sixteen","seventeen","eighteen",
         "nineteen"]

    set2 = ["","","twenty","thirty","forty","fifty","sixty",
         "seventy","eighty","ninety"]

    thousands = (int/1000)
    hundreds = ((int%1000) / 100)
    tens = ((int % 100) / 10)
    ones = int % 10
    string = ""

    string += set1[thousands] + " thousand " if thousands != 0 if thousands > 0
    string += set1[hundreds] + " hundred" if hundreds != 0
    string +=" and " if tens != 0 || ones != 0 
    string = string + set1[tens*10+ones] if tens < 2
    string += set2[tens]
    string = string + " " + set1[ones] if ones != 0     
    string << 'zero' if int == 0    
    p string
end

以测试为目的；

n_to_s(rand(9999))

Answer 3

由于String#to_i只选择数字字符，因此它不会以您想要的方式工作。可能有一些 Rails 方法与此相关，但它肯定不会有方法名称to_i，因为它的行为会与String#to_i.

不仅Strings如此to_i。NilClass, Time, Float, Rational（也许还有其他一些类）也可以。

"3".to_i #=> 3
"".to_i #=> 0
nil.to_i #=> 0
Time.now.to_i #=> 1353932622
(3.0).to_i #=> 3
Rational(10/3).to_i #=> 3

Answer 4

这是一个简单的字符串查找到它们的数字等价物：

str_to_int_hash = {
  'zero'  => 0,
  'one'   => 1,
  'two'   => 2,
  'three' => 3,
  'four'  => 4,
  'five'  => 5,
  'six'   => 6,
  'seven' => 7,
  'eight' => 8,
  'nine'  => 9,
  'ten'   => 10
}

str_to_int_hash['ten']
=> 10

很明显还有许多其他缺失的条目，但它说明了这个想法。

如果你想从一个数字转到字符串，这是起点：

int_to_str_hash = Hash[str_to_int_hash.map{ |k,v| [v,k] }]
int_to_str_hash[10]
=> "ten"