ruby 字串學習2

標籤：

在一個ruby字串中包含表但是或者變數。想使用不同的值替換運算式或者變數 

 

1 類似java 或者python的printf-style方式

template = ‘Oceania has always been at war with %s.‘template % ‘Eurasia‘ # => "Oceania has always been at war with Eurasia."template % ‘Eastasia‘ # => "Oceania has always been at war with Eastasia."
‘To 2 decimal places: %.2f‘ % Math::PI # => "To 2 decimal places: 3.14"

‘Zero-padded: %.5d‘ % Math::PI  # => "Zero-padded: 00003"

2 或者使用erb，因為我用的ide，所以最後一行使用的是kernel.binding ，如果你在irb中，可以只使用binding

require ‘erb‘template = ERB.new %q{Chunky <%= food %>!}food = "bacon"puts output = template.result(Kernel.binding)

 3翻轉字串

s = ".sdrawkcab si gnirts sihT"s.reverse # => "This string is backwards."s  # => ".sdrawkcab si gnirts sihT"s.reverse! # => "This string is backwards."s  # => "This string is backwards."

s = "order. wrong the in are words These"s.split(/(\s+)/).reverse!.join(‘‘) # => "These words are in the wrong order."s.split(/\b/).reverse!.join(‘‘) # => "These words are in the wrong. order"

(\s+)和\s+區別，(\s+)匹配的空格會包含返回列表中

"Three little words".split(/\s+/)# => ["Three", "little", "words"]"Three little words".split(/(\s+)/)# => ["Three", " ", "little", " ", "words"]

 

ruby 字串學習2