Let’s get into the string operations in Lua. It’s a bit beyond the scope of this article to list out every possibility for string.format. Let’s see this all in practice: If you want to get a single character at a specific position, set “i” and “j” to the same number. WoW Lua string.gsub(s, pattern, replace [, n]) gsub(s, pattern, replace [, n]) strreplace(s, pattern, replace [, n]) This is a very powerful function and can be used in multiple ways. Patterns, which are similar in function to Regex (though far more lightweight), are a way to search for various substrings based on specified information. Luckily, there is a good UTF8 library which can be installed via Luarocks. It’s also hard to deal with lengths and similar. If repl is a string, then its value is used for replacement. Let’s also look at some of the less commonly used string functions which we won’t spend much time on. You should try to memorize at least a few of the operations as soon as possible. Let’s see an example of something easy: Don’t worry about understanding all of this yet. Read the previous lesson on classes to make sure you understand what this is and why this works. All gists Back to GitHub Sign in Sign up Sign in Sign up {{ message }} Instantly share code, notes, and snippets. This is an interesting feature of Lua which allows some functions to take extra arguments as necessary. Substitute strings inside another string. This type of function is extremely useful for writing a basic parser. A sample code for character and byte representation, which is used for converting the string from string to internal representation and vice versa. %% becomes %. Let’s see a quick example: Before we can dive too far into the rest of our common string functions, we need to understand the basics of patterns and how to handle special characters in Lua. Greedy matching is useful when you want everything between something even if it would match and end case. string string.Replace( string str, string find, string replace ) View Source Search Github DescriptionReplaces all occurrences of the supplied second string. A sample code for manipulating the strings to upper and lower case is given below. string.format takes a string s which contains special sequences to format the string. In our string before, we have “123” then a bunch of extra stuff and end with “123” for the test string. Let’s start with a table and introduce each function as we go. We match a digit via %d and look for 1 or more repetitions with our magic character (“+”). That’s great, but pretty much useless, let’s throw in a pattern or two: Let’s throw in some magic characters and spice things up! Used simply it can replace all instances of the pattern provided with the replacement. This is useful when you have sequences of similar formatting (think tags in a string or similar). utf8.find Don’t worry, we’re going to go over all of these. When indexing a string in Lua, the first character is at position 1, not at position 0 as in C. Indices are allowed to be negative and are interpreted as indexing backwards from the end of the string. Returns a copy of str with matches to 'pattern' replaced by 'replacement', for a maximum of n times. We look for at least one digit, then anything, then another digit. Repeat “s” n times. There are other options, but I have excluded them due to their rarity, and due to the fact some are not implemented/applicable in Lua. They aren't unique to Lua, in fact they're used across many languages and tools and have solid roots in automata theory. N8Gamez. VADemon / string-replace.lua. Replace string.lower with string.upper if you would like the text field to be all uppercase. String is a sequence of characters as well as control characters like form feed. Recommended Posts. This table is just to get you used to what all is on the table. Try working with these on your own to see what they do. Lua offers a wide range of functions for working with text. The next example collects all pairs key=value from the given string into a table: t = {} s = "from=world, to=Lua" for k, v in string.gmatch (s, " (%w+)= (%w+)") do t [k] = v end I’ve never used any of these, but I’m including them for completion’s sake. What would you like to do? Most languages require you to pass an array or similar, but Lua has a built in way to handle this. First let's take a look at the string.find function in general: The function string.find (s, substr [, init [, plain]]) returns the start and end index of a substring if found, and nil otherwise, starting at the index init if it is provided (defaults to 1). The character %works as an escape character: any sequence in replof the form %n, with nbetween 1and 9, stands for the value of the nthcaptured substring. Last active Oct 23, 2019. We’ve gone through all of the cool string features in Lua, and we can work with UTF8 if we don’t need certain things, but what happens when we need true unicode support? Prototype. A negative index means start from the back, so -1 would be the last character. And vice versa - ” tells us to match any number of seconds time! Form feed the search begins, and the number of arguments a maximum of n )! Share ; Posted May 25, 2020 source string according to the user 's.... ', lua string replace a lot, but we ’ re greedy so we a! To Vimscript types ( and lua string replace versa true Official Modification Forum rules have some new exercises coming to... Below, but let ’ s hard to break strings down on character... 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