6.6 File Input/Output

Documentation

• Julia 1.0 Programming: Chapter 8 (I/O, Networking, and Parallel Computing)

  • Sign in for Brown University access to O'Reilly

• Introducing Julia Wikibook: Working with text files

• Julia Base: I/O and Network

Theory: Reading and Writing Files

• Note: Using Julia Base functions only

UCI Machine Learning Repository: Adult Data Set

• Tabulate and report counts for sex in Adult Data Set

Dataset (adult.data)

39, State-gov, 77516, Bachelors, 13, Never-married, Adm-clerical, Not-in-family, White, Male, 2174, 0, 40, United-States, <=50K
50, Self-emp-not-inc, 83311, Bachelors, 13, Married-civ-spouse, Exec-managerial, Husband, White, Male, 0, 0, 13, United-States, <=50K
38, Private, 215646, HS-grad, 9, Divorced, Handlers-cleaners, Not-in-family, White, Male, 0, 0, 40, United-States, <=50K
53, Private, 234721, 11th, 7, Married-civ-spouse, Handlers-cleaners, Husband, Black, Male, 0, 0, 40, United-States, <=50K
28, Private, 338409, Bachelors, 13, Married-civ-spouse, Prof-specialty, Wife, Black, Female, 0, 0, 40, Cuba, <=50K

Input (process_file.jl)

# process_file.jl
# Tabulate and report counts for sex in Adult Data Set
# https://archive.ics.uci.edu/ml/datasets/adult

# relative path of file
data_file = open("_data/adult/adult.data", "r")

# absolute path of file
# data_file = open("/Users/user/data/adult/adult.data", "r")

# initialize collection (dictionary for tabulating counts)
gender_dict = Dict()

# read each line, extract sex, and keep track of counts
for line in readlines(data_file)

  # skip empty lines
  if isempty(line)
      continue
   end

  # split line into array, based on delimiter (comma and space)
  line_array = split(line, ", ")

  # tabulate the counts for gender
  gender = line_array[10]
  if haskey(gender_dict, gender)
    gender_dict[gender] += 1
  else
    gender_dict[gender] = 1
  end
end

# report total counts
println("Sort by key (alphabetical):")
for gender in keys(gender_dict)
  println("  $gender = $(gender_dict[gender])")
end

# report total counts by key, in reverse order
println("Sort by key (reverse alphabetical):")
for gender in sort(collect(keys(gender_dict)), rev=true)
  println("  $gender = $(gender_dict[gender])")
end

# report total counts by value, in reverse order (send output to file)
output_file = open("process_file_output.txt", "w")
println("Sort by value (reverse numerical):")
for (count, gender) in sort(collect(zip(values(gender_dict),keys(gender_dict))), rev=true)
  println("  $gender = $(gender_dict[gender])")
  write(output_file, "$gender = $count\n")
end

Output

Sort by key (alphabetical):
  Female = 10771
  Male = 21790
Sort by key (reverse alphabetical):
  Male = 21790
  Female = 10771
Sort by value (reverse numerical):
  Male = 21790
  Female = 10771

From BIDSS Manual (Need to Modify)

Terminal

$ julia process_file.jl
Sort by key (alphabetical):
  Female = 10771
  Male = 21790
Sort by key (reverse alphabetical):
  Male = 21790
  Female = 10771
Sort by value (reverse numerical):
  Male = 21790
  Female = 10771

$ ls -1
process_file.jl
process_file_output.txt

$ more process_file_output.txt
Male = 21790
Female = 10771