Write an anonymous function (a "function literal")
to return the third value in a list. You may assume that the list has at least three elements.
(fn [x] (first (rest (rest x))))
(fn [x] (nth x 2))
Write a function named
neg to return the first negative number in a list of numbers. You may assume that the list contains some negative numbers.
(defn neg [lst]
(if (< (first lst) 0)
(neg (rest lst)) ) )
- Write an anonymous function that, given a positive integer
N, will return a list or sequence (either one) of the integers
(fn [n] (take n (iterate inc 1)))
(fn [n] (range 1 (inc n)))
- Give the function defined in the previous question the name
count-to. Then use
count-to to write an expression whose value is a list of squares of the numbers
100. That is, it returns
[1 4 9 16 ... 10000].
(def count-to (fn [n] (range 1 (inc n))))
(map (fn [x] (* x x)) (count-to 100))
(for [x (count-to 100)] (* x x))
- Define a function
non-mult-3 with argument
N which returns true if
N is not a multiple of
3. Reminder: Clojure has
not functions that you can use.
(defn non-mult-3 [x] (not (zero? (mod x 3))))
- Use the previously defined functions to compute the product of the numbers
25 that are not multiples of
(reduce * (filter non-mult-3 (count-to 25)))
- Briefly, what does it mean to say that "a transaction is atomic"?
Viewed from another thread, either all the actions in the transaction have completed, or none have.
- Briefly, what is a reference varable (
A mutable pointer to immutable data.
- The real problem with the Java approach to concurrency is that
___________________________ + ___________________________ = ___________________________.
(fill in the blanks).
- Write a tail-recursive function named
sum to add up all the numbers in a list of numbers. Hint: Define
sum to have two parameters, and use one of them as an "accumulator."