ruby首字母大写

str.capitalize! → str or nil

Modifies str by converting the first character to uppercase and the remainder to lowercase. Returns nil if no changes are made. Note: case conversion is effective only in ASCII region.

   a = "hello"
   a.capitalize!   #=> "Hello"
   a               #=> "Hello"
   a.capitalize!   #=> nil

【推广】 免费学中医，健康全家人
原文地址：https://www.cnblogs.com/lexus/p/1951627.html