Read the File contents and process the data in Ruby

Question

How to process the data between the lines starting with File Id one by one. My below code gives output for 1st section , what if there are 100 + sections separated by File Id:.

Its like I want to take the 1st section arrange the data then take up the 2nd section (File ID) and so on. if there is a better way I would surely listen to it. Thanks.

Input file (input.txt)

File Id: C:/my_files/00_Roll_Tom-values.txt

#RakeBoss-Random as on 12/19/2016
[groups]
met = chk\rel_io_chk, chk\dev_op_io,
div = chk\kzhr2x, chk\zz52t0, chk\czzjrt
rakeonly = chk\rzgnsd, chk\cztw5h

[/]
@met = rw
@div = rw
@rakeonly = r

File Id: C:/my_files/Rander-values.txt

#RakeBoss-Jan 21st QA
[groups]
met = chk\rel_io_chk, chk\dev_op_io
div = chk\541kmj, chk\zz52t0
app_only = chk\zz9ycd
check_io = chk\wder4, chk\zz9ycd
div_write = chk\lo98j3
year_on = chk\3w345f
[/]
@met = rw
@div = rw
@app_only= r
@check_io = r
@div_write = rw
@year_on = r

[/wedmin]
@check_io = rw
div_write= rw

[/doc/prod]
@div = rw
@app_only = r
year_on = rw

File Id: C:/my_files/456_Milo_123-values.txt

#RakeBoss-Jan 21st Prod
[groups]
met = chk\rel_io_chk, chk\dev_op_io
div = chk\kzhr2x, chk\zz52t0, chk\czzjrt, chk\pzjwr3
jee_only = chk\zz9ycd, chk\hz659l, chk\zzktgj, 
check_io = chk\8u7y01, chk\zz9ycd
unique_key = chk\zz9ycd
year_on = chk\dytg6
[/]
@met = rw
@div = rw
@rakeonly = r

[/Release]
@check_io = rw
@unique_key = rw

[/Redmine/Treehub]
@div = r
@jee_only = rw

.............
...................
............. so on separated by File Id:

Code

File.open("input.txt", "r") do |f|
  fight_info = f.read
  m = fight_info.match(/File\sId(.+?)File\sId/m)
  puts m
end

How big can the input file be? If it's guaranteed to always fit into memory you can "slurp" it using `read`, but usually files in production systems shouldn't be handled that way. — the Tin Man, Jun 19 '17 at 18:17

score 1 · Accepted Answer · answered Jun 19 '17 at 08:16

You could make a method to abstract the reading of the file and splitting it up into sections:

def split_by_file_id(file)
  lines = []
  id = nil
  File.foreach(file).with_index do |line, line_num|
    if line =~ /^File Id: (.*)/m
      yield id, lines if id
      lines = []
      id = $1
    else
      lines << line if id
    end      
  end
  yield id, lines if id
end

# Code to process each section...
split_by_file_id("input.txt") do |id, lines|
  lines.each do |line|
    # do something...
  end
end

Thanks much, Any idea how to organize data in the [groups] and in [/] Eg, from section 1, scm, dev, readonly should be assigned to array called id with its corresponding values one by one — voltas, Jun 19 '17 at 09:35

score 0 · Answer 2 · edited Jun 19 '17 at 18:20

0

file = File.open("input.txt", "rb")
contents = file.read.split("File Id:")
contents.shift

Now you can do contents.each to loop through it.

edited Jun 19 '17 at 18:20

the Tin Man

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answered Jun 19 '17 at 11:48

Ravi Shrivastava

41
6

Be _very_ careful doing this. Using `read` pulls in the entire file into memory which can destroy performance. See https://stackoverflow.com/q/25189262/128421 – the Tin Man Jun 19 '17 at 18:20

Read the File contents and process the data in Ruby

2 Answers2