Finding certain ruby word in txt file - ruby

Question

I am trying to create a ruby tool that goes through a file looking for a certain string, and if it finds that word than it stores it in a variable. If NOT then it prints “word not found” on the console. Is this possible? How can i code this?

Answer 1

You can use File#open method and readlinesmethod like this.
test.txt
This is a test string.
Lorem imsum.
Nope.
code
def get_string_from_file(string, file_path)
File.open(file_path) do |f|
f.readlines.each { |line| return string if line.include?(string) }
end
nil
end
file_path = './test.txt'
var = get_string_from_file('Lorem', file_path)
puts var || "word not found"
# => "Lorem"
var = get_string_from_file('lorem', file_path)
puts var || "word not found"
# => "word not found"
I hope this heps.

Answer 2

Here's few examples of how you could find a certain word in a text file using IO from the Ruby core: http://ruby-doc.org/core-2.3.1/
In find_word_in_text_file.rb:
# SETUP
#
filename1 = 'file1.txt'
filename2 = 'file2.txt'
body1 = <<~EOS
PHRASES
beside the point
irrelevant.
case in point
an instance or example that illustrates what is being discussed: the “green revolution” in agriculture is a good case in point.
get the point
understand or accept the validity of someone's idea or argument: I get the point about not sending rejections.
make one's point
put across a proposition clearly and convincingly.
make a point of
make a special and noticeable effort to do (a specified thing): she made a point of taking a walk each day.
EOS
body2 = <<~EOS
nothing to see here
or here
or here
EOS
# write body to file
File.open(filename1, 'w+') {|f| f.write(body1)}
# write file without matching word
File.open(filename2, 'w+') {|f| f.write(body2)}
# METHODS
#
# 1) search entire file as one string
def file_as_string_rx(filename, string)
# http://ruby-doc.org/core-2.3.1/Regexp.html#method-c-escape
# http://ruby-doc.org/core-2.3.1/Regexp.html#method-c-new
rx = Regexp.new(Regexp.escape(string), true) # => /whatevs/i
# read entire file to string
# http://ruby-doc.org/core-2.3.1/IO.html#method-i-read
text = IO.read(filename)
# search entire file for string; return first match
found_word = text[rx]
# print word or default string
puts found_word || "word not found"
# —OR—
#STDOUT.write found_word || "word not found"
#STDOUT.write "\n"
end
# 2) search line by line
def line_by_line_rx(filename, string)
# http://ruby-doc.org/core-2.3.1/Regexp.html#method-c-escape
# http://ruby-doc.org/core-2.3.1/Regexp.html#method-c-new
rx = Regexp.new(Regexp.escape(string), true) # => /whatevs/i
# create array to store line numbers of matches
matches_array = []
# search each line for string
# http://ruby-doc.org/core-2.3.1/IO.html#method-c-readlines
#lines = IO.readlines(filename)
#
# http://ruby-doc.org/core-2.3.1/Enumerable.html#method-i-each_with_index
# http://stackoverflow.com/a/5546681/1076207
# "Be wary of "slurping" files. That's when you
# read the entire file into memory at once.
# The problem is that it doesn't scale well.
#lines.each_with_index do |line,i|
#
# —OR—
#
# http://ruby-doc.org/core-2.3.1/IO.html#method-c-foreach
i = 1
IO.foreach(filename) do |line|
# add line number if match found within line
matches_array.push(i) if line[rx]
i += 1
end
# print array or default string
puts matches_array.any? ? matches_array.inspect : "word not found"
# —OR—
#STDOUT.write matches_array.any? ? matches_array.inspect : "word not found"
#STDOUT.write "\n"
end
# RUNNER
#
string = "point"
puts "file_as_string_rx(#{filename1.inspect}, #{string.inspect})"
file_as_string_rx(filename1, string)
puts "\nfile_as_string_rx(#{filename2.inspect}, #{string.inspect})"
file_as_string_rx(filename2, string)
puts "\nline_by_line_rx(#{filename1.inspect}, #{string.inspect})"
line_by_line_rx(filename1, string)
puts "\nline_by_line_rx(#{filename2.inspect}, #{string.inspect})"
line_by_line_rx(filename2, string)
# CLEANUP
#
File.delete(filename1)
File.delete(filename2)
Command line:
$ ruby find_word_in_text_file.rb
file_as_string_rx("file1.txt", "point")
point
file_as_string_rx("file2.txt", "point")
word not found
line_by_line_rx("file1.txt", "point")
[3, 6, 7, 9, 10, 12, 15, 16]
line_by_line_rx("file2.txt", "point")
word not found