Hash in Ruby & Convert python to ruby -

i using hash in ruby, check whether word in “pairs” class , replace them. code in python , want convert ruby not familiar with. here ruby code wrote.

import sys  pairs = {'butter' => 'flies', 'cheese' => 'wheel', 'milk'=> 'expensive'}  line in sys.stdin:     line_words = line.split(" ")     word in line_words:       if word in pairs         line = line.gsub!(word, pairs[word])  puts line 

it shows following error

syntax error, unexpected kin, expecting kthen or ':' or '\n' or ';'       if word in pairs                 ^ 

while below original python script right:

import sys  pairs = dict()  pairs = {'butter': 'flies', 'cheese': 'wheel', 'milk': 'expensive'}  line in sys.stdin:   line = line.strip()   line_words = line.split(" ")   word in line_words:     if word in pairs:       line = line.replace(word ,pairs[word])  print line  

is because of "import sys" or “indentation”？

try this:

pairs = {'butter' => 'flies', 'cheese' => 'wheel', 'milk'=> 'expensive'}  line = argv.join(' ').split(' ').map |word|   pairs.include?(word) ? pairs[word] : word end.join(" ")  puts line 

this loop on each item passed script , return word or replacement word, joined space.