CODEWITHSUNDEEP
luaio
zpx
zpx

Reputation: 25

why the function io.write() does not work in lua

I want to count the number of occurrences of words in a text and give the top ten words and their number of occurrences.

I use the function io.open() to open a input file as file-handle, then do something on the file-handle, put the results in a table. then close the input file-handle. and open a output file which is a new file as file-handle try to write the results to this file. but it does not work. the code is following.

the txt "ioinput.txt" is input file which has a article and the txt "iooutput.txt" is the output file

input_file = io.open("ioinput.txt", r)

--[[
This block of code is to count the number of word,
which has been verified by the print function in the following.
--]]

input_file:close()

output_file = io.open("iooutput.txt", a)

local n = 10
for i = 1, n do
    output_file:write(words[i], "\t", counter[words[i]], "\n")
    --print(words[i], "\t", counter[words[i]], "\n")
end
output_file:flush()
output_file:close()

Upvotes: 0

Views: 315

Answers (1)

Piglet
Piglet

Reputation: 28950

Please refer to the Lua 5.4 Reference Manual: io.open

io.open (filename [, mode])

This function opens a file, in the mode specified in the string mode. In case of success, it returns a new file handle.

The mode string can be any of the following:

"r": read mode (the default);
"w": write mode;
"a": append mode;
"r+": update mode, all previous data is preserved;
"w+": update mode, all previous data is erased;
"a+": append update mode, previous data is preserved, writing is only allowed at the end of file.

The mode string can also have a 'b' at the end, which is needed in some systems to open the file in binary mode.

Please note that the optional mode is to be provided as a string.

In your code

input_file = io.open("ioinput.txt", r) and output_file = io.open("ioinput.txt", a)

your using modes r and a. Both nil values. The mode defaults to "r" which is read mode. You cannot write to a file opened in read mode.

Upvotes: 1

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