Getting a substring of an attribute in XPATH

Question

Given

How do I all but the last 4 characters of @baz? One of my attempts was:<

Answer 1

try this: substring-before(/foo/bar/@baz,"rld!")

Answer 2

That's actually not so bad, but IIRC substring doesn't like negative indices. I tried

substring(/foo/bar/@baz, string-length(/foo/bar/@baz)-4)

Which gave me the expected result.

Answer 3

Use:

substring(/foo/bar/@baz, string-length(/foo/bar/@baz)-3) 

Do note the 3 in the expression.

The following is wrong:

substring(/foo/bar/@baz, string-length(/foo/bar/@baz)-4) 

because this returns the last 5 characters of the string value of the baz attribute.