4.10 Pairs and Lists Pairs and Lists in The Racket Guide introduces pairs and lists. (Note: numbers are words. (see, Return a string spaced to a given width (see, (Special form) Are all of the arguments true values (i.e., not. Apply a function to each element of a word or Create a vector with the arguments as elements. �(a b c)) 0 (+ 1 (length �(b c)))) = (+ 1 (length �(b c))) = (+1 (if (null? Return an element of a vector (counting from zero). Read a line from the keyboard (or a file), returning a sentence. make-node Create a new node of a tree. This table does not represent the complete Scheme language. ), Print the argument in machine-readable form (see. Raise the first argument to the power of the second. (definelength ��� (lambda(L) ��������� (if(null?
The most general notation (external representation) for Scheme pairs is the "dotted" notation (c1. procedure. Return all but the first element of a list. Select a subset of a word or sentence (see. Is the argument a word? Join the arguments together into a big sentence. Is the first argument less than or equal to the second? list (see. Show the argument sentence without surrounding parentheses. Return the absolute value of the argument. Defining Scheme Functions Handout written by Jerry Cain, Ben Newman, and David Hall.
e.g. Return the number of times the first argument is in the second. Return first letter of a word, or first word of a sentence. Is the argument a list?
Does the first argument come alphabetically before the second? (see. Return the sine of a number (from trigonometry). We can write a range of useful functions using just cons, car, and cdr. lengthcounts the number of top-level elements in a list. standard ones that are not needed here.
list? L) �������������� 0 �������������� (+ 1(length (tail L)))))) A derivation of this function is a series of equalities,each one obtained from the one before by substituting values for theparameters. instructions (see. second? Return a list with the same elements as the vector. Return association list entry matching key.
log Return the logarithm of a number. Return last letter of a word, or last word of a sentence. Scheme provides the built-in function list which returns a list of its arguments: > (list 1 2 3 4) (1 2 3 4) > (cons 1 (cons 2 (cons 3 (cons 4 '())))) ; equivalent, but tedious (1 2 3 4) list can take any number of arguments. Is the first argument greater than or equal to the second? Is the first argument greater than the second? Return all but the last letter of a word, or word of a sentence. Return the remainder from dividing the first number by the second. Is the argument empty, i.e., the empty word. Return a list of the children of a tree node.
(Special form) Create a global name (for a procedure or other value). (Special form) Choose among several alternatives Return a list containing the elements of the argument lists.
(Special form) Create a new procedure (see Chapter \lambchop). (see.
Apply a function to each element of a list (see, Return subset of a list starting with selected element, or, Is the first argument an element of the Apply a combining function to all elements
Return a vector with the same elements as the list. Apply a function to the arguments in a list. list-ref Select an element from a list (counting from zero). It includes the
Perform a computation for each element of a list. sentence (see. A pair combines exactly two values. �(b c)) 0 (+1 (length �(c)))))) = (+ 1 (+ 1 (length �(c)))… (length�(a b c)) = (if (null? Print the argument without starting a new line. Read a line from the keyboard (or a file), returning a string. nonstandard Scheme primitives that we use in this book, and it omits many
Return the cosine of a number (from trigonometry). Read an expression from the keyboard (or a file). Return a random number ≥ 0 and smaller than the argument. Round a number up to the nearest integer. Return the number of elements in a vector. Select an element from a list (counting from zero). load Read a program file into Scheme. Return the number of letters in a word or number of words in a sentence.
make-vector Create a new The first value is accessed with the car procedure, and the second value is accessed with the cdr procedure. (Special form) Carry out a sequence of Obviously Scheme wouldn’t be of much use to us if all we ever did were compare strings and confirm that numbers like 222 are integers Apply a combining function to all elements of