ruby 字串學習2

c3tc3tc3t發表於2015-11-30
字串

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表示式或者變數 

 

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"]

 

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