Ruby正则表达式怎样处理字符串

在Ruby中，使用正则表达式处理字符串非常常见。以下是一些关于如何在Ruby中使用正则表达式的例子：

1. 查找字符串中的匹配项：

str = "Hello, my name is Ruby."
regex = /Ruby/
match = str.match(regex)

if match
  puts "Found match: #{match[0]}"
else
  puts "No match found"
end

2. 查找字符串中所有匹配项：

str = "There are 3 Rubies and 5 Rubies in the basket."
regex = /Ruby/gi
matches = str.scan(regex)

puts "Found #{matches.size} matches:"
puts matches.join(', ')

3. 替换字符串中的匹配项：

str = "I like cats, cats are cute."
regex = /cats/
replacement = "dogs"
new_str = str.gsub(regex, replacement)

puts "Original string: #{str}"
puts "New string: #{new_str}"

4. 使用捕获组：

str = "The price of the item is $40."
regex = /\$(\d+)/
matches = str.scan(regex)

if matches
  puts "Found matches:"
  matches.each do |match|
    puts "Price: $#{match[0]}"
  end
else
  puts "No match found"
end

这些例子展示了如何在Ruby中使用正则表达式处理字符串。你可以根据需要调整正则表达式和替换字符串来完成不同的任务。