WoW:API strfind: Difference between revisions

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{{:Lua/Libshortcut|strfind|string.find}}
{{luaapi}}
  string.find(s, pattern [, init [, plain]])
  string.find(s, pattern [, init [, plain]])
strfind(s, pattern [, init [, plain]])


Find the first occurrence of the pattern in the string passed. If an instance of the pattern is found a pair of values representing the start and end of the string is returned. If the pattern cannot be found nil is returned.
Find the first occurrence of the pattern in the string passed. If an instance of the pattern is found a pair of values representing the start and end of the string is returned. If the pattern cannot be found nil is returned.
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  firstWord = "Phase2"
  firstWord = "Phase2"
  restOfString = "There isn't any need for iterating over this mini-string."
  restOfString = "There isn't any need for iterating over this mini-string."
{{LUA}}

Revision as of 22:40, 25 March 2010

WoW Lua

string.find(s, pattern [, init [, plain]])
strfind(s, pattern [, init [, plain]])

Find the first occurrence of the pattern in the string passed. If an instance of the pattern is found a pair of values representing the start and end of the string is returned. If the pattern cannot be found nil is returned.

> = string.find("Hello Lua user", "Lua")
7       9
> = string.find("Hello Lua user", "banana")
nil

We can optionally specify where to start the search with a third argument. The argument may also be negative which means we count back from the end of the string and start the search.

> = string.find("Hello Lua user", "Lua", 1)  -- start at first character
7       9
> = string.find("Hello Lua user", "Lua", 8)  -- "Lua" not found again after character 8
nil
> = string.find("Hello Lua user", "e", -5)   -- first "e" 5 characters from the end
13      13

The pattern argument can be a regular expression which allows more complex searches. See the Patterns Tutorial on Lua-Users.org and Pattern matching for more information. We can turn off the regular expression feature by using the optional fourth argument plain. plain takes a boolean value and must be preceded by init. E.g.,

> = string.find("Hello Lua user", "%su")          -- find a space character followed by "u"
10      11
> = string.find("Hello Lua user", "%su", 1, true) -- turn on plain searches, now not found
nil

Example

Sometimes it's more appropriate to use string.find, rather than string.gmatch, eg:

local msg = "Phase2:- There isn't any need for iterating over this mini-string.";
local startPos, endPos, firstWord, restOfString = string.find( msg, "(%w+)[%s%p]*(.*)");

Result

startPos = 1
endPos = 66
firstWord = "Phase2"
restOfString = "There isn't any need for iterating over this mini-string."