lstrip : 去掉首空格
rstrip : 去掉尾空格
gsub : 去掉全部空格,不过要用到pattern匹配
a = " hello world "
puts a.lstrip => "hello world "
puts a.rstrip => " hello world"
puts a.lstrip.rstrip => "hello world"
puts a.gsub(/\s+/,'') => "helloworld"
puts a.gsub(' ','') => "helloworld"
puts a.gsub(//,'') => "helloworld"
写了多个空格，传上去就成一个空格了。
