Golang正则表达式匹配字符串，直到给定的字符序列

Question

I have a string that could have a -name followed by value (that can have spaces) and there could also be -descr after that followed by a value (the -descr followed by value may nor may not be there):

Example strings:

runcmd -name abcd xyz -descr abc def

or

runcmd -name abcd xyz

With Go language, how do I write regexp, that returns me the string before -descr if it exists. so, for both examples above, the result should be:

runcmd -name abcd xyz

I was trying:

regexp.MustCompile(`(-name ).+?=-descr`)

But, that did not return any match. I wanted to know the correct regexp to get the string up until -descr if it exists

Answer 1

You could capturin first part with -name in a group, then match what is in between and use an optional second capturing group to match -descr and what follows.

Then you could use the capturing groups when creating the desired result.

^(.*? -name\b).*?(-descr\b.*)?$

Regex demo | Go demo

For example:

s := "runcmd -name abcd xyz -descr abc def"
re1 := regexp.MustCompile(`^(.*? -name\b).*?(-descr\b.*)?$`)
result := re1.FindStringSubmatch(s)
fmt.Printf(result[1] + "..." + result[2])

Result:

runcmd -name...-descr abc def