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- Lua - Modes for File Access
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Lua - Open File
Lua provides I/O library to read and manipulate files. In this article, we'll checkout the ways to open a file.
we will use a sample file example.txt as shown below−
example.txt
Welcome to tutorialspoint.com Simply Easy Learning
Complete Model - Open File In Read Mode
Let us now see how to open a file in read mode first.
main.lua
-- read a file content and returns the same function readFile() -- Opens a file in read f = io.open("example.txt","r") -- read all the contents contents = f:read("*all") -- close the file handle f:close() -- return the contents return contents end -- read the file and get the contents contents = readFile() -- print the contents print(contents)
Output
When the above code is built and executed, it produces the following result −
Welcome to tutorialspoint.com Simply Easy Learning
Here we've used following code
-- Opens a file in read f = io.open("example.txt","r")
We can open a file without r mode as well as shown below−
-- Opens a file in read f = io.open("example.txt")
io.open() function opens the file and returns a file handle. Using file handle we can read the content of the file, write content to the file which will clear the existing content and write the new one or append content over existing one.
This mode, where we're using a file handle to perform File I/O is called Complete Model. There is one Simple Model as well where we're not using the file handle.
Simple Model - Open File In Read Mode
In simple mode, we use io.input() to set as a default input file or io.output() to set as default output file. Let's re-write the above example using simple model.
main.lua
-- read a file content and returns the same function readFile() -- Opens a file in read f = io.open("example.txt","r") -- sets the default input file as test.lua io.input(f) -- read all the contents contents = io.read("*all") -- close the file handle io.close(f) -- return the contents return contents end -- read the file and get the contents contents = readFile() -- print the contents print(contents)
Output
When the above code is built and executed, it produces the following result −
Welcome to tutorialspoint.com Simply Easy LearningHere we've used io.read(), io.close() methods instead of file handle specific methods like file:read() and file:close() methods.