有没有不同的方法可以通过使用默认值初始化哈希的键来编写下面的代码？

Question

>编写一个返回字符串中使用的各种小写、大写、数字和特殊字符 no 的方法。利用范围。

输入 = "heLLo every1">

我正在提供的解决方案中使用范围和案例方法。

溶液：

class String
  def character_count
    uppercase_count = 0
    lowercase_count = 0
    digit_count = 0
    uppercase_range = Range.new('A', 'Z')
    lowercase_range = Range.new('a', 'z')
    digit_range = Range.new('0', '9')
    special_character_count = 0
    each_char do |item|
      case item
      when uppercase_range
        uppercase_count += 1
      when lowercase_range
        lowercase_count += 1
      when digit_range
        digit_count += 1
      else
        special_character_count += 1
      end
    end
    [lowercase_count, uppercase_count, digit_count, special_character_count]
  end
end
if ARGV.empty?
  puts 'Please provide an input'
else
  string = ARGV[0]
  count_array = string.character_count
  puts "Lowercase characters = #{count_array[0]}"
  puts "Uppercase characters = #{count_array[1]}"
  puts "Numeric characters = #{count_array[2]}"
  puts "Special characters = #{count_array[3]}"
end

代码正在工作。

Answer 1

是

class String
  def character_count
    counters = Hash.new(0)
    each_char do |item|
      case item
      when 'A'..'Z'
        counters[:uppercase] += 1
      when 'a'..'z'
        counters[:lowercase] += 1
      when '0'..'9'
        counters[:digit] += 1
      else
        counters[:special] += 1
      end
    end
    counters.values_at(:uppercase, :lowercase, :digit, :special)
  end
end
if ARGV.empty?
  puts 'Please provide an input'
else
  string = ARGV[0]
  uppercase, lowercase, digit, special = string.character_count
  puts "Lowercase characters = #{lowercase}"
  puts "Uppercase characters = #{uppercase}"
  puts "Numeric characters = #{digit}"
  puts "Special characters = #{special}"
end

Answer 2

您可以更好地使用regex，如下所示，

type = { special: /[^0-9A-Za-z]/, numeric: /[0-9]/, uppercase: /[A-Z]/, lowercase: /[a-z]/ }
'Hello World'.scan(type[:special]).count
# => 1 
'Hello World'.scan(type[:numeric]).count
# => 0 
'Hello World'.scan(type[:uppercase]).count
# => 2
'Hello World'.scan(type[:lowercase]).count
# => 8 

Answer 3

其他选项。

首先，将范围映射到哈希中：

mapping = { upper: ('A'..'Z'), lower: ('a'..'z'), digits: ('0'..'9'), specials: nil }

然后将收件人哈希初始化为默认0：

res = Hash.new(0)

最后，映射输入的字符：

input = "heLLo Every1"
input.chars.each { |e| res[(mapping.find { |k, v| v.to_a.include? e } || [:specials]).first ] += 1 }
res
#=> {:upper=>3, :lower=>7, :digits=>1, :specials=>1}

Answer 4

str = "Agent 007 was on the trail of a member of SPECTRE"

str.each_char.with_object(Hash.new(0)) do |c,h|
  h[ case c
     when /d/     then :digit
     when /p{Lu}/ then :uppercase
     when /p{Ll}/ then :downcase
     else               :special
     end
   ] += 1
  end
end
  #=> {:uppercase=>8, :downcase=>28, :special=>10, :digit=>3}