package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)^
(?:
[+-]? # optional sign
(?: # start a conditional group
\d+ # either a nonzero number of digits
| # or a decimal phrase
\d* # optional digits preceding the decimal
\.(?=\d) # a literal decimal followed by at least one digit
\d* # optionally some more digits
) # note this group is mandatory!
(?: # start an optional scientific notation group
[eE] # the scientific notation character
[+-]? # optional sign
\d+ # after sci notation, you cannot go directly to a decimal
)?
)
$`)
var str = `67
-4
91.32
.67
-0.1123
4e5
71e-43
-323.456e-4.5
e
54e34e2
543.
43.e23
--323
e655
54e.3
-43e`
for i, match := range re.FindAllString(str, -1) {
fmt.Println(match, "found at index", i)
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/