string find doesn't return the expected result

Question

I'm tryng to check in lua if AGM-65D is found in "LAU-117,AGM-65D"

but string.find("LAU-117,AGM-65D", "AGM-65D") and string.match("LAU-117,AGM-65D", "AGM-65D")

both return nil. Does someone could suggest me why? maybe the comma or the "-" symbol must be used in a different way?

thanks

string.find("LAU-117,AGM-65D", "AGM-65D", 1, true)

Egor Skriptunoff
– Egor Skriptunoff

2018-12-26 13:16:59 +00:00
Commented Dec 26, 2018 at 13:16 — Egor Skriptunoff
– Egor Skriptunoff, Commented Dec 26, 2018 at 13:16

Vlad · Accepted Answer · 2018-12-27 11:21:14Z

2

Both string.find and string.match will search for a pattern, and not for a plain string. And your search fails because symbol - is a special character in pattern matching.

To make it work, "escape" special characters with % sign, make it "AGM%-65D"

edit: A comment from Egor reminds us there's optional argument to string.find to make it search for a plain text. In simple search cases it should be preferred.

edited Dec 27, 2018 at 11:21

answered Dec 26, 2018 at 12:43

Vlad

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3 Comments

user3204845 Over a year ago

Thanks! sadly I got the "AGM-65D" string from another chunk, so I need to find a way to replace - with %-. string.gsub obviously didn't do that.

user3204845 Over a year ago

found!... I had to escape the escape character, so: string.gsub("AGM-65D", "-", "%%-" ) produces "AGM%-65D" as needed

Vlad Over a year ago

@user3204845 See the comment from Egor, there's often overlooked option that makes string.find to search for plain texts :)

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