正则表达式模式未捕获匹配的第二次出现

Question

我有一个字符串：

Error: heroku 6.14.38 is already installed
To upgrade to 7.7.1, run `brew upgrade heroku`

我正在做.slice(/([\d+\.]+)/)，它给了我6.14.38，而不是7.7.1。

我怎么也可以得到它？

Answer 1

您可以使用scan方法：

str = "Error: heroku 6.14.38 is already installed
To upgrade to 7.7.1, run `brew upgrade heroku`"
puts(str.scan(/((?:\d+\.)+\d+)/))

打印：

6.14.38
7.7.1

Answer 2

str = "Error: heroku 6.14.38 is already installed
To upgrade to 7.7.1, run `brew upgrade heroku`"

r = /
    \d{1,2}  # match one or two digits
    \.       # match decimal
    \d{1,2}  # match two digits
    \.       # match decimal
    \d{1,2}  # match two digits
    .+?      # match any number of characters, lazily
    \K       # discard match so far
    \d{1,2}  # match one or two digits
    \.       # match decimal
    \d{1,2}  # match two digits
    \.       # match decimal
    \d{1,2}  # match two digits
    /xm      # free-spacing regex definition and multiline modes

str[r]
  #=> "7.7.1"