# What is a list in racket?

The list is the fundamental data structure of Racket. A list is a sequence of values. A list can contain any kind of value, including other lists. A list can contain any number of values. If a list has zero values, it’s called the empty list.

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## Secondly, what is CDR and car in Scheme?

In Scheme, car , cdr , and cons are the most important functions. … car is an acronym from the phrase Contents of the Address part of the Register; and cdr is an acronym from the phrase Contents of the Decrement part of the Register.

Herein, why is racket recursion preferred? Recursion is a favored technique in functional programming because it helps avoid mutation of values.

## In this regard, what is Check expect in racket?

A check-expect expression must be placed at the top-level of a student program. Also it may show up anywhere in the program, including ahead of the tested function definition. … It is an error for expr or expected-expr to produce an inexact number or a function value.

## What is lambda in racket?

In Racket (and other functional programming languages) lambda s are very useful, when you want to pass an in-line, one-shot function as a parameter without defining it first. For example, suppose that we want to square a list of numbers.

## What is map in racket?

The map function walks a list (or multiple lists), and applies a given function to every value of a list. For example mappiing add1 to a list results in: > (map add1 ‘(1 2 3 4)) ‘(2 3 4 5)

## What does cons mean in Lisp?

In computer programming, cons (/ˈkɒnz/ or /ˈkɒns/) is a fundamental function in most dialects of the Lisp programming language. cons constructs memory objects which hold two values or pointers to values. These objects are referred to as (cons) cells, conses, non-atomic s-expressions (“NATSes”), or (cons) pairs.

## What does CDR mean in Lisp?

In computer programming, CAR ( car ) /kɑːr/ ( listen) and CDR ( cdr ) (/ˈkʌdər/ ( listen) or /ˈkʊdər/ ( listen)) are primitive operations on cons cells (or “non-atomic S-expressions”) introduced in the Lisp programming language.

## Does CDR return a list?

The CDR of a list is the rest of the list, that is, the cdr function returns the part of the list that follows the first item. … Like car , cdr does not remove any elements from the list—it just returns a report of what the second and subsequent elements are. Incidentally, in the example, the list of flowers is quoted.

## How does append work in racket?

The append function joins two lists together to make one.

The append function is built into Scheme. It concatenates two lists, that is to say, given two lists list1 and list2 it produces a new list which starts with the same elements as list1 and finishes with those of list2 .