红宝石 |字符串 gsub！方法

gsub！是 Ruby 中的 String 类方法，用于返回给定字符串的副本，其中所有出现的模式都替换为第二个参数。如果没有执行替换，那么它将返回 nil。如果没有给出块并且没有给出替换，则返回一个枚举器。

Syntax: str.gsub!(pattern, replacement)

Parameters: Here, str is the given string. pattern may be specified regex or character set to be removed. replacement is the set of characters which is to be put.

Returns: A copy of the string with all occurrences of pattern substituted for the second argument or nil if no substitutions were performed.

示例 1：

# Ruby program to demonstrate 
# the gsub! method 
       
# Taking a string and 
# using the method
puts "Sample".gsub!(/[bcd]/, '*')                 
puts "Program".gsub!(/([gmra])/, '<\1>')      

输出：

Po

示例 2：

# Ruby program to demonstrate 
# the gsub! method 
       
# Taking a string and 
# using the method
puts "Ruby".gsub!(/[tyru]/, '<\1>')                 
puts "String".gsub!(/([ab])/, '*')     

输出：

Rb