上午/下午將24位整數轉換爲12小時

Question

我使用的是紅寶石。

我試圖找出如何以下轉換..

14成爲2 pm

0成爲12 am

23成爲11 pm

謝謝！

Answer 1

[14, 0, 23].map { |hour| Time.parse("#{hour}:00").strftime("%l %P") } 
=> [" 2 pm", "12 am", "11 pm"] 

Answer 2

def convert h 
    p, l = h.divmod(12) 
    "#{l.zero? ? 12 : l} #{p.zero? ? "a" : "p"}m" 
end 
convert(14) # => "2 pm" 
convert(0) # => "12 am" 
convert(23) # => "11 pm" 

Answer 3

我喜歡@森的答案，因爲它可以讓時間做繁重，但使用的基準，我們可以看到這是最CPU密集型：

這是我採寫：

def am_pm(hour) 
    meridian = (hour >= 12) ? 'pm' : 'am' 
    hour = case hour 
     when 0, 12 
      12 
     when 13 .. 23 
      hour - 12 
     else 
      hour 
     end 

    "#{ hour } #{ meridian }" 
end 

基準：

require 'benchmark' 
require 'time' 

def mori(hour) 
    Time.parse("#{hour}:00").strftime("%l %P") 
end 

def convert h 
    p, l = h.divmod(12) 
    "#{l.zero? ? 12 : l} #{p.zero? ? "a" : "p"}m" 
end 

def am_pm(hour) 
    meridian = (hour >= 12) ? 'pm' : 'am' 
    hour = case hour 
     when 0, 12 
      12 
     when 13 .. 23 
      hour - 12 
     else 
      hour 
     end 

    "#{ hour } #{ meridian }" 
end 

def hour_24_to_12(hour_24) 
    hour_12 = hour_24 - 12 

    if hour_12 == 0 
    return "12 pm" 
    elsif hour_12 == -12 
    return "12 am" 
    elsif hour_12 > 0 
    return "#{hour_12} pm" 
    elsif hour_12 < 0 
    return "#{hour_24} am" 
    else 
    # The passed-in time is outside the range o 0-23, 
    # so you may need to deal with this however you 
    # feel is appropriate 
    end 
end 

HRS = [0, 14, 23] 
N = 100_000 

puts RUBY_VERSION 

HRS.each { |hr| puts "am_pm:   #{ am_pm(hr)   }" } 
HRS.each { |hr| puts "convert:  #{ convert(hr)  }" } 
HRS.each { |hr| puts "hour_24_to_12: #{ hour_24_to_12(hr) }" } 
HRS.each { |hr| puts "mori:   #{ mori(hr)   }" } 

Benchmark.bm(13) do |b| 
    b.report('am_pm')   { N.times { HRS.each { |h| am_pm(h)   } } } 
    b.report('convert')  { N.times { HRS.each { |h| convert(h)  } } } 
    b.report('hour_24_to_12') { N.times { HRS.each { |h| hour_24_to_12(h) } } } 
    b.report('mori')   { N.times { HRS.each { |h| mori(h)   } } } 
end 

，輸出：

1.9.3 
am_pm:   12 am 
am_pm:   2 pm 
am_pm:   11 pm 
convert:  12 am 
convert:  2 pm 
convert:  11 pm 
hour_24_to_12: 12 am 
hour_24_to_12: 2 pm 
hour_24_to_12: 11 pm 
mori:   12 am 
mori:   2 pm 
mori:   11 pm 
        user  system  total  real 
am_pm   1.230000 0.000000 1.230000 ( 1.228159) 
convert   1.280000 0.000000 1.280000 ( 1.286672) 
hour_24_to_12 0.640000 0.000000 0.640000 ( 0.642993) 
mori   20.940000 0.020000 20.960000 (21.003620) 

而且相同的測試僅在2.0的Ruby-P0運行：

2.0.0 
am_pm:   12 am 
am_pm:   2 pm 
am_pm:   11 pm 
convert:  12 am 
convert:  2 pm 
convert:  11 pm 
hour_24_to_12: 12 am 
hour_24_to_12: 2 pm 
hour_24_to_12: 11 pm 
mori:   12 am 
mori:   2 pm 
mori:   11 pm 
        user  system  total  real 
am_pm   0.440000 0.000000 0.440000 ( 0.433303) 
convert   0.410000 0.000000 0.410000 ( 0.412183) 
hour_24_to_12 0.200000 0.000000 0.200000 ( 0.201894) 
mori   9.910000 0.010000 9.920000 ( 9.921940)