CoffeeScript 推导式

for student,i in [element1, element2, element3]

for student,i in ['Ram', 'Mohammed', 'John']
   console.log "The name of the student with id "+i+" is: "+student 

c:\> coffee-c for_in_index.coffee

// Generated by CoffeeScript 1.10.0
(function() {
  var i, j, len, ref, student;
  ref = ['Ram', 'Mohammed', 'John'];
  for (i = j = 0, len = ref.length; j < len; i = ++j) {
    student = ref[i];
    console.log("The name of the student with id " + i + " is: " + student);
  }
}).call(this);

c:\> coffee for_in_index.coffee

The name of the student with id 0 is: Ram
The name of the student with id 1 is: Mohammed
The name of the student with id 2 is: John 

#Postfix for..in comprehension
console.log student for student in ['Ram', 'Mohammed', 'John']
#postfix for..of comprehension
console.log key+"::"+value for key,value of { name: "Mohammed", age: 24, phone: 9848022338}

my_function =->
   student = ['Ram', 'Mohammed', 'John']
   
   #Assigning comprehension to a variable
   names = (x for x in student )
   console.log "The contents of the variable names are ::"+names
   
   #Returning the comprehension
   return x for x in student
console.log "The value returned by the function is "+my_function() 

c:\> coffee-c example.coffee

// Generated by CoffeeScript 1.10.0
(function() {
  var my_function;
  my_function = function() {
    var i, len, names, student, x;
    student = ['Ram', 'Mohammed', 'John'];
    names = (function() {
      var i, len, results;
      results = [];
      for (i = 0, len = student.length; i < len; i++) {
        x = student[i];
        results.push(x);
      }
      return results;
    })();
    console.log("The contents of the variable names are ::" + names);
    for (i = 0, len = student.length; i < len; i++) {
      x = student[i];
      return x;
    }
  };
  console.log("The value returned by the function is " + my_function());
}).call(this);

c:\> coffee example.coffee

The contents of the variable names are ::Ram,Mohammed,John
The value returned by the function is Ram 

array = (num for num in [1..10] by 2)
console.log array

c:\> coffee-c by_keyword_example.coffee

// Generated by CoffeeScript 1.10.0
(function() {
  var array, num;
  array = (function() {
    var i, results;
    results = [];
    for (num = i = 1; i <= 10; num = i += 2) {
      results.push(num);
    }
    return results;
  })();
  console.log(array);
}).call(this);

c:\> coffee by_keyword_example.coffee

[ 1, 3, 5, 7, 9 ]