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lambda calc Cheat Sheet (DRAFT) by

lambda calculus programmming

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Clojure Basics

(str "­Hel­lo" " " "­Wor­ld")
Math operators +, -, /, *
 
(quote (+ 1 2)) or '(+ 1 2) or `(+ 1 2)
 
(eval `(+ 1 2)) => 3
 
(def x 1)
 
(defn hello [name] (str "­Hello " name))
 
(defn hello2 [& args] 
    (for [x args] (hello x)))
 
(apply <fn> <ar­gs>)
(apply + [1 2 3])
 
(if <co­nd> <ex­p1> <ex­p2>)
false => false, nil
 
(case grade
    :A "Great"
    :B "Good"
    :C "OK"
    "Not good")
 
(cond
    (>= grade 90) "Great"
    (>= grade 80) "Good"
    :else "Need Work")
 
(for [x (range 10) 
   :let [y (+ x 2)]
   :when (< y 5)] y)
 
(for [x (range 3) 
      y (range 2)] [x y])
 
(for [x (range 10) 
   :let [y (+ x 2)]
   :while­(< y 5)] y)
 

Destru­cturing

(first seq)
=> 1
 
(rest seq)
=> (234)
 
(nth seq 2)
=> 3
 
(last seq)
=> 4
 
(take 2 seq)
=> (1 2)
 
(drop 2 seq)
=> (2 3)
 
(take-­while (fn [x] ( < x 3) seq)

=> (1 2))
 
(filter even? seq)
=> (2 4)
Vectors as functions
(vect 2)
=> 3
 
(nth vect 2)
 
(get vect 2)
 
(subvec vect 2 4)
=> [3 4]
Maps 
(get my-map :key)
 
(my-map :key)
(:key my-map)
Nested Map 
(get-in my-map [:outer :inner])
Nested with vector 
(get-in my-map [:outer n :inner])
 
(keys my-map)
 
(vals my-map)