If I have this string: "wwww:xxxx:yyyy:zzzzzz:0"

How can I return only the "zzzzzz:0" value? Knowing that zzzzz will not always be the same length.

CodePudding user response：

Use Patterns for this:

 string.match("wwww:xxxx:yyyy:zzzzzz:0", "[^:] :[^:] $")  --> 'zzzzzz:0'

This is naïve but will work in the simplest use cases. [^:] matches a sequence of one or more characters that are not :, : after that matches itself, and $ matches the end of the string.

Based on the format of your string, you might actually want to look into separating the string into a table using : as separator. This can be accomplished with e.g., string.gmatch and the [^:] pattern from above.

In a complex situation where the components are expected to e.g., support quoting or escape sequences you might want to use a full-pledged csv-like parser instead.

CodePudding user response：

Try also this somewhat simpler pattern:

string.match("wwww:xxxx:yyyy:zzzzzz:0", ". :(. :. )$")

It looks for the last item of the form foo:bar.