Question

我正在使用Ruby on Rails应用程序。在我正在调用API的地方的应用程序中，我将字符串作为Up 4.35% from Oct to Nov返回给我。我的要求是当我在用户界面上显示时，我需要将其显示为Up 4.35% from October to November。

有人可以告诉我该怎么做？

Answer 1

Date::MONTHNAMES也许可以帮到你。如果它们总是3个字符缩短版本的月份，您可以构建一个哈希来帮助：

dates = Date::MONTHNAMES.compact.map { |m| [m[0..2], m] }.to_h

然后在别处使用它：

text = 'Up 4.35% from Oct to Nov'
text.gsub(/#{dates.keys.join('|')}/, dates)
=> "Up 4.35% from October to November"

Answer 2

您可以使用gsub。

只需延长我所有月份的例子：

"Up 4.35% from Oct to Nov".gsub(/Oct|Nov/) do |s| 
  {'Oct' => 'October', 'Nov' => 'November'}[s]
end
# => "Up 4.35% from October to November"

Answer 3

您需要

String#sub

试试这个：

a = "Up 4.35% from Oct to Nov"
a.sub('Oct', 'October').sub('Nov', 'November') # you can continue with other months
#=> "Up 4.35% from October to November"

Answer 4

人们不会注意这种特殊的gsub能力，所以请冥想：

SHORT_TO_LONG_MONTH_NAMES = %w[
  January
  February
  March
  April
  May
  June
  July
  August
  September
  October
  November
  December
].map{ |m| [m[0, 3], m] }.to_h
# => {"Jan"=>"January", "Feb"=>"February", "Mar"=>"March", "Apr"=>"April", "May"=>"May", "Jun"=>"June", "Jul"=>"July", "Aug"=>"August", "Sep"=>"September", "Oct"=>"October", "Nov"=>"November", "Dec"=>"December"}

SHORT_TO_LONG_MONTH_NAMES_REGEX = /\b(?:#{ Regexp.union(SHORT_TO_LONG_MONTH_NAMES.keys).source })\b/
# => /\b(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\b/

str = 'Up 4.35% from Oct to Nov'

str.gsub(SHORT_TO_LONG_MONTH_NAMES_REGEX, SHORT_TO_LONG_MONTH_NAMES)
# => "Up 4.35% from October to November"

以简洁的方式去除输出结果，以快速搜索和替换文档：

SHORT_TO_LONG_MONTH_NAMES = %w[
  January
  February
  March
  April
  May
  June
  July
  August
  September
  October
  November
  December
].map{ |m| [m[0, 3], m] }.to_h

SHORT_TO_LONG_MONTH_NAMES_REGEX = /\b(?:#{ Regexp.union(SHORT_TO_LONG_MONTH_NAMES.keys).source })\b/

str = 'Up 4.35% from Oct to Nov'

str.gsub(SHORT_TO_LONG_MONTH_NAMES_REGEX, SHORT_TO_LONG_MONTH_NAMES)
# => "Up 4.35% from October to November"

旧红宝石没有to_h所以你可以使用它：

SHORT_TO_LONG_MONTH_NAMES = Hash[%w[
  January
  February
  March
  April
  May
  June
  July
  August
  September
  October
  November
  December
].map{ |m| [m[0, 3], m] }]
# => {"Jan"=>"January", "Feb"=>"February", "Mar"=>"March", "Apr"=>"April", "May"=>"May", "Jun"=>"June", "Jul"=>"July", "Aug"=>"August", "Sep"=>"September", "Oct"=>"October", "Nov"=>"November", "Dec"=>"December"}

分解正则表达式模式生成：

SHORT_TO_LONG_MONTH_NAMES_REGEX = /\b(?:#{ Regexp.union(SHORT_TO_LONG_MONTH_NAMES.keys).source })\b/

\b是一个分词或词边界，意思是单词的开头或结尾。 A＆＃34;字＆＃34;是字符集[a-zA-Z0-9_]，AKA \w，字断点是前一个非单词字符和单词字符之间的分界线。没有做到这一点是各种人类苦难的根源;子字符串将在没有\b的情况下匹配，因此您可以获得各种有趣的替换。
(?:...)定义了一个非捕获组，这是查找一系列备用模式的好方法，在这种情况下，它是三个字母缩短的月份名称列表。
Regexp.union是一个有用的方法，它接受一个数组，在本例中是哈希的键，并用|分隔它们，Regexp.union是模式中的OR符号。基本上它意味着任何键都可以匹配。
source是其中非常重要的一部分。如果没有它，/foo/i # => /foo/i /#{ /foo/i }/ # => /(?i-mx:foo)/ /foo/i.source # => "foo" /#{ /foo/i.source }/ # => /foo/的结果（它是一个编译的正则表达式）将被插入到字符串中，以及其相关的标志，这可能导致冲突的搜索。考虑一下这些之间的区别：
```
(?i-mx:
```
第一种是不区分大小写的模式。第二种是嵌入在区分大小写的情况下的不区分大小写的模式，但source在内部将其标记为不敏感。这是一个等待的错误，除非你确定这是你想要的。

require 'date' Date::ABBR_MONTHNAMES.zip(Date::MONTHNAMES)[1..-1].to_h # => {"Jan"=>"January", "Feb"=>"February", "Mar"=>"March", "Apr"=>"April", "May"=>"May", "Jun"=>"June", "Jul"=>"July", "Aug"=>"August", "Sep"=>"September", "Oct"=>"October", "Nov"=>"November", "Dec"=>"December"} Hash[Date::ABBR_MONTHNAMES.zip(Date::MONTHNAMES)[1..-1]] # => {"Jan"=>"January", "Feb"=>"February", "Mar"=>"March", "Apr"=>"April", "May"=>"May", "Jun"=>"June", "Jul"=>"July", "Aug"=>"August", "Sep"=>"September", "Oct"=>"October", "Nov"=>"November", "Dec"=>"December"} /\b(?:#{ Regexp.union(Date::ABBR_MONTHNAMES[1..-1]).source }\b)/ # => /\b(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec\b)/返回没有标志的模式的字符串化版本，因此最终结果是我们实际期望的结果。

之前我已经被咬过了，追踪是一件很大的痛苦。

最后，Date类有一些预定义的常量，这样你就不必像我上面那样用long-hand定义哈希。这是为了明确发生了什么，但为方便起见，你可以做以下事情：

[1..-1]

请注意在样本中使用{{1}}。这是因为为了我们的查找乐趣，数组包含第一个值的nil，以使数组基于1而不是基于0，但如果您尝试使用数组，这会使Ruby嚎叫对于模式。

Answer 5

def replace(string)
    string.gsub("Jan", "January").gsub("Feb", "February").gsub("Mar", "March").gsub("Apr", "April").gsub("Jul", "July").gsub("Aug", "August").gsub("Sep", "September").gsub("Oct", "October").gsub("Nov", "November").gsub("Dec", "December")
end

str = "Up 4.35% from Oct to Nov"

最后，只需调用函数：

replace(str)

从Ruby中的字符串中提取月份名称

5 个答案: