Delete a line of information from a text file

Question

I have a text file called text.txt, and it has the following text:

123,shirt,9.99 
234,pants,19.50
456,socks,3.99

How do I delete one row (e.g 123,shirt,9.99). How would I go about deleting this row?

My code so far:

 test_file = File.new('text.txt', "a")
 while (line = test_file)
   puts 'Enter the products item number you wish to delete. '
   user_delete = gets.chomp.to_i
   line.delete(user_delete)
 end

'a' simply appends to the file, it won't remove anything. – Anthony Mar 04 '15 at 00:34 — Anthony, Mar 04 '15 at 00:34
so if i want to delete something out do i use 'r+' ? – Kyren Johnson Mar 04 '15 at 00:48 — Kyren Johnson, Mar 04 '15 at 00:48

score 1 · Answer 1 · edited May 23 '17 at 12:24

1

You're making a lot of mistakes here.

First of all opening the file with a (you need to use r+ or w+).

In Ruby we use a more elegant to iterate over files.

Check this answer, it will help you with your problem.

After that a look at IO library to understand how it all works

edited May 23 '17 at 12:24

Community

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answered Mar 04 '15 at 01:13

Guilherme Carlos

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score 1 · Answer 2 · answered Mar 04 '15 at 01:13

1

I imagine there are a bunch of better ways to do this, but here's quick and dirty:

puts "What's the item number?"
item_num = gets.chomp

read_file = File.new('read.txt', "r").read
write_file = File.new('read.txt', "w")

read_file.each_line do |line|
  write_file.write(line) unless line.include? item_num
end

answered Mar 04 '15 at 01:13

orde

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awesome, exactly what i was looking for. Basically just reading the file and re writing it up to the item number. Thanks! – Kyren Johnson Mar 04 '15 at 01:23
NP. Feel free to accept and/or upvote this answer if it addressed your issue. – orde Mar 04 '15 at 17:55

Delete a line of information from a text file

2 Answers2

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