i read multipe file and i try to get data in yaml file, but i dont know why i get nothing in my yaml file .
Do you have an idea where i can make a mistake ?
a = array.size
i = 0
array.each do |f|
while i < a
puts array[i]
output = File.new('/home/zyriuse/documents/Ruby-On-Rails/script/Api_BK/licence.yml', 'w')
File.readlines(f).each do |line|
output.puts line
output.puts line.to_yaml
#output.puts YAML::dump(line)
end
i += 1
end
end
There's two problems...
You are initializing i to zero too early... when you process the
first file 'f' you process JUST that first file as many times as you
have files in the array, but for all following files i is now always >= a so you're not doing anything with them.
You are doing File.new in every iteration of 'f' so you are wiping out your last iteration.
This might work better...
output = File.new('licence.yml', 'w')
array.each do |f|
puts f
File.readlines(f).each do |line|
output.puts line
output.puts line.to_yaml
end
end
Related
I have my file
ppp.txt
mmm;2;nsfnjd;pet;
sadjjasjnsd;6;gdhjsd;pet;
gsduhdssdj;3;gsdhjhjsd;dog;
I need to write
nsfnjd
gsdhjhjsd
I use this code but only print the last line "gsdhjhjsd"
I dont know what is doing wrong
File.open("ppp.txt", "r") do |fi|
fi.readlines.each do |line|
parts = line.chomp.split(';')
if parts[1].to_i < 4
puts parts[2]
File.open("testxx.txt", "w+") do |f|
f. puts parts[2]
end
end
end
end
Please help me
Open the file using append mode, 'a+' instead of write mode 'w+', which overwrites the file, as the open command is called inside a loop.
Or open the write file prior to looping the lines of the read file.
open the file descriptor outside the loop
fo = File.open("testxx.txt","w+")
File.open("ppp.txt", "r") do |fi|
fi.readlines.each do |line|
parts = line.chomp.split(';')
fo.puts parts[2] if parts[1].to_i < 4
end
end
fo.close()
NOTE: Need to explicitly close fo, but file open with block; ruby close the file automatically (fi case).
I am trying to import a large text file (approximately 2 million rows of numbers at 260MB) into an array, make edits to the array, and then write the results to a new text file, by writing:
file_data = File.readlines("massive_file.txt")
file_data = file_data.map!(&:strip)
file_data.each do |s|
s.gsub!(/,.*\z/, "")
end
File.open("smaller_file.txt", 'w') do |f|
f.write(file_data.map(&:strip).uniq.join("\n"))
end
However, I have received the error failed to allocate memory (NoMemoryError). How can I allocate more memory to complete the task? Or, ideally, is there another method I can use where I can avoid having to re-allocate memory?
You can read the file line by line:
require 'set'
require 'digest/md5'
file_data = File.new('massive_file.txt', 'r')
file_output = File.new('smaller_file.txt', 'w')
unique_lines_set = Set.new
while (line = file_data.gets)
line.strip!
line.gsub!(/,.*\z/, "")
# Check if the line is unique
line_hash = Digest::MD5.hexdigest(line)
if not unique_lines_set.include? line_hash
# It is unique so add its hash to the set
unique_lines_set.add(line_hash)
# Write the line in the output file
file_output.puts(line)
end
end
file_data.close
file_output.close
You can try reading and writing one line at once:
new_file = File.open('smaller_file.txt', 'w')
File.open('massive_file.txt', 'r') do |file|
file.each_line do |line|
new_file.puts line.strip.gsub(/,.*\z/, "")
end
end
new_file.close
The only thing pending is find duplicated lines
Alternatively you can read file in chunks which should be faster compared to reading it line by line:
FILENAME="massive_file.txt"
MEGABYTE = 1024*1024
class File
def each_chunk(chunk_size=MEGABYTE) # or n*MEGABYTE
yield read(chunk_size) until eof?
end
end
filedata = ""
open(FILENAME, "rb") do |f|
f.each_chunk() {|chunk|
chunk.gsub!(/,.*\z/, "")
filedata += chunk
}
end
ref: https://stackoverflow.com/a/1682400/3035830
I am trying to log some state to a file using standard file i/o in ruby. The file will just have one line with a number in it. I want to read in the line and then on each iteration of a loop I want to update this number.
I know I can read in the file with
file = File.open('out.log', 'a+')
num = file.readline
The problem is, I don't know how to then overwrite the first line in a loop without just re-opening the file every iteration i.e.
file = File.open('out.log', 'w')
which will create an empty file
No need to open it each time:
file = File.open('out.log', File::RDWR)
10.times do |i|
file.seek(0) # rewind to the beginning of the file (line in your case)
file.write("iteration #{i}") # write what you want
# the following is just in order to show what was written
file.seek(0)
puts file.readline
end
file.close
You can use IO::open with block to close the file, when block exits automatically.
File.open("#{__dir__}/test.txt", File::RDWR) do |file|
10.times do |i|
file.rewind
file.puts("iteration #{i}")
end
end
puts File.read("#{__dir__}/test.txt")
# >> iteration 9
I am trying to read file lines from a directory containing about 200 text files, however, I can't get Ruby to read them line-by-line. I did it before, using one text file, not reading them from a directory.
I can get the file names as strings, but I am struggling to open them and read each line.
Here are some of the methods I've tried.
Method 1:
def readdirectory
#filearray = []
Dir.foreach('mydirectory') do |i|
# puts i.class
#filearray.push(i)
#filearray.each do |s|
# #words =IO.readlines('s')
puts s
end#do
# puts #words
end#do
end#readdirectory
Method 2:
def tryread
Dir.foreach('mydir'){
|x| IO.readlines(x)
}
end#tryread
Method 3:
def tryread
Dir.foreach('mydir') do |s|
File.readlines(s).each do |line|
sentence =line.split
end#inner do
end #do
end#tryread
With every attempt to open the string passed by the loop function, I keep getting the error:
Permission denied - . (Errno::EACCES)
sudo ruby reader.rb or whatever your filename is.
Since permissions are process based you can not read files with elevated permissions if the process reading does not have them.
Only solutions are either to run the script with more permissions or call another process which is already running with higher permissions to read for you.
Thanks for all replies,I did a bit of trial and error and got it to work.This is the syntax I used
Dir.entries('lemmatised').each do |s|
if !File.directory?(s)
file = File.open("pathname/#{s}", 'r')
file.each_line do |line|
count+=1
#words<<line.split(/[^a-zA-Z]/)
end # inner do
puts #words
end #if
end #do
Try this one,
#it'll hold the lines
f = []
#here test directory contains all the files,
#write the path as per the your computer,
#mine's as you can see, below
#fetch filenames and keep in sorted order
a = Dir.entries("c:/Users/lordsangram/desktop/test")
#read the files, line by line
Dir.chdir("c:/Users/lordsangram/desktop/test")
#beginning for i = 1, to ignore first two elements of array a,
#which has no associated file names
2.upto(a.length-1) do |i|
File.readlines("#{a[i]}").each do |line|
f.push(line)
end
end
f.each do |l|
puts l
end
#the Tin Man -> you need to avoid processing "." and ".." which are listed in Dir.foreach and give the permission denied error. A simple if should fix all your apporoaches.
Dir.foreach(ARGV[0]) do |f|
if f != "." and f != ".."
# code to process file
# example
# File.open(ARGV[0] + "\\" + f) do |file|
# end
end
end
Hi just getting into Ruby, and I am trying to learn some basic file reading commands, and I haven't found any solid sources yet.
I am trying to go through certain lines from that file, til the end of the file.
So in the file where it says FILE_SOURCES I want to read all the sources til end of file, and place them in a file.
I found printing the whole file, and replacing words in the file, but I just want to read certain parts in the file.
Usually you follow a pattern like this if you're trying to extract a section from a file that's delimited somehow:
open(filename) do |f|
state = nil
while (line = f.gets)
case (state)
when nil
# Look for the line beginning with "FILE_SOURCES"
if (line.match(/^FILE_SOURCES/))
state = :sources
end
when :sources
# Stop printing if you hit something starting with "END"
if (line.match(/^END/))
state = nil
else
print line
end
end
end
end
You can change from one state to another depending on what part of the file you're in.
I would do it like this (assuming you can read the entire file into memory):
source_lines = IO.readlines('source_file.txt')
start_line = source_lines.index{ |line| line =~ /SOURCE_LINE/ } + 1
File.open( 'other_file.txt', 'w' ) do |f|
f << source_lines[ start_line..-1 ].join( "\n" )
end
Relevant methods:
IO.readlines to read the lines into an array
Array#index to find the index of the first line matching a regular expression
File.open to create a new file on disk (and automatically close it when done)
Array#[] to get the subset of lines from the index to the end
If you can't read the entire file into memory, then I'd do a simpler variation on #tadman's state-based one:
started = false
File.open( 'other_file.txt', 'w' ) do |output|
IO.foreach( 'source_file.txt' ) do |line|
if started then
output << line
elsif line =~ /FILE_SOURCES/
started = true
end
end
end
Welcome to Ruby!
File.open("file_to_read.txt", "r") {|f|
line = f.gets
until line.include?("FILE_SOURCES")
line = f.gets
end
File.open("file_to_write.txt", "w") {|new_file|
f.each_line {|line|
new_file.puts(line)
}
new_file.close
}
f.close
}
IO functions have no idea what "lines" in a file are. There's no straightforward way to skip to a certain line in a file, you'll have to read it all and ignore the lines you don't need.