Category
Forum Posts

How to Multiply Lists Of Lists Together In Erlang?

In Erlang, you can multiply lists of lists together by using list comprehensions or recursive functions. Here's an explanation of the process:

1. Using list comprehensions: Define two lists of lists that you want to multiply, for example, ListA and ListB. Iterate over both lists simultaneously using a list comprehension. Multiply corresponding elements from each list and create a new list containing the multiplied values. Repeat this process for each inner list. The final result will be a new list of lists containing the multiplied values.
2. Using recursive functions: Define a recursive function that takes two lists of lists as parameters. Extract the first element from each list of lists. Multiply the extracted elements and add the result to a new list. Call the recursive function again with the remaining elements of the lists. Repeat this process until all elements are multiplied. The final result will be a new list of lists containing the multiplied values.

Both approaches provide a way to multiply lists of lists in Erlang, and you can choose the one that suits your requirements and coding style.

Best Erlang Books to Read in 2024

1

Rating is 5 out of 5

Handbook of Neuroevolution Through Erlang

2

Rating is 4.9 out of 5

Designing for Scalability with Erlang/OTP: Implement Robust, Fault-Tolerant Systems

3

Rating is 4.8 out of 5

Learn You Some Erlang for Great Good!: A Beginner's Guide

4

Rating is 4.7 out of 5

Erlang Programming: A Concurrent Approach to Software Development

5

Rating is 4.6 out of 5

Introducing Erlang: Getting Started in Functional Programming

6

Rating is 4.5 out of 5

Erlang and OTP in Action

7

Rating is 4.4 out of 5

Programming Erlang: Software for a Concurrent World

8

Rating is 4.3 out of 5

Programming Erlang: Software for a Concurrent World (Pragmatic Programmers)

How to multiply lists element-wise in Erlang?

One way to multiply lists element-wise in Erlang is to use a loop and recursively multiply the corresponding elements of the two lists. Here is an example implementation:

 ``` 1 2 3 4 5 6 7 8 9 10 ``` ```-module(multiply_lists). -export([multiply/2]). multiply(List1, List2) -> multiply(List1, List2, []). multiply([], [], Result) -> lists:reverse(Result); multiply([X|Xs], [Y|Ys], Result) -> multiply(Xs, Ys, [X*Y|Result]). ```

In this example, the `multiply/2` function takes two input lists and calls the helper function `multiply/3` with an additional empty list `[]` as the initial accumulator. The `multiply/3` function defines two base cases: when both lists are empty, it returns the accumulated result after reversing it using `lists:reverse/1`; and when both lists have elements, it multiplies the corresponding elements and appends the result to the accumulator. It then makes a recursive call with the remaining elements of both lists and the updated accumulator.

How to multiply a list of lists with a non-square matrix in Erlang?

To multiply a list of lists with a non-square matrix in Erlang, you can use the following code:

 ``` 1 2 3 4 5 6 7 8 9 10 11 ``` ```% Function to multiply a list of lists with a non-square matrix multiply_lists(Matrix, Lists) -> lists:map(fun(List) -> multiply_list(Matrix, List) end, Lists). % Helper function to multiply a single list with a matrix multiply_list(Matrix, List) -> lists:flatten(lists:zipwith(fun(Row, Value) -> multiply_row(Row, Value) end, Matrix, List)). % Helper function to multiply a row of the matrix with a value multiply_row(Row, Value) -> lists:map(fun(X) -> X * Value end, Row). ```

Here's how you can use the above code:

 ```1 2 3 4 ``` ```Matrix = [[2, 4, 6], [1, 3, 5], [7, 8, 9], [0, -1, 2]], Lists = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]], Result = multiply_lists(Matrix, Lists). ```

In this example, `Matrix` represents the non-square matrix and `Lists` is the list of lists you want to multiply with the matrix. The `multiply_lists` function takes in both `Matrix` and `Lists` and returns the result of multiplying each list in `Lists` with the Matrix. The `multiply_list` function is a helper function that multiplies a single list with the matrix by performing element-wise multiplication of each row in the matrix with the corresponding value in the list. Finally, the `multiply_row` function is another helper function that performs the element-wise multiplication of a row in the matrix with a single value.

The `Result` variable will contain the resulting list of lists after the multiplication.

What is the result of multiplying an empty list in Erlang?

The result of multiplying an empty list in Erlang is usually an error. In Erlang, the multiplication operator (*) is used for arithmetic operations, so attempting to multiply an empty list will throw a badarith error. This is because multiplication is not defined for lists in Erlang.

What is the operator used for list multiplication in Erlang?

In Erlang, the operator used for list multiplication is the `++` operator. This operator is used to concatenate two lists together. Here's an example of how it is used:

 ```1 2 3 ``` ```List1 = [1, 2, 3], List2 = [4, 5, 6], Concatenated = List1 ++ List2. ```

In this example, the `++` operator is used to concatenate `List1` and `List2`, resulting in the list `[1, 2, 3, 4, 5, 6]`.

Related Posts:

To create Erlang views in CouchDB, you need to perform the following steps:Install Erlang: Erlang is a programming language that is commonly used to create CouchDB views. You need to install the Erlang runtime environment on your system before you can create E...
To install Erlang Observer on a Mac, you can follow these steps:The first step is to download and install Erlang. You can visit the official Erlang website (https://www.erlang.org/downloads) and download the latest stable version for Mac. Once Erlang is instal...
Working with lists and tuples in Erlang is a core aspect of the language. Lists and tuples are both fundamental data types in Erlang and have their own unique characteristics and uses.Lists:Lists in Erlang are represented by a sequence of elements enclosed in ...