# Data Types - Matrices - Week 1: Background, Getting.

A matrix or data frame combining the. arguments column-wise or row-wise. For cbind (rbind) the column (row) names are taken from the names of the arguments, or where those are not supplied by deparsing the expressions given (if that gives a sensible name). The names will depend on whether data frames are included: see the examples.

Details. Similar to rbind.fill.matrix, but works for Matrix as well as all other R objects. It is completely agnostic to class, and will produce an object of the class of the first input (or of class matrix if the first object is one dimensional). The implementation is recursive, so it can handle an arbitrary number of inputs, albeit inefficiently for large numbers of inputs. Let be a matrix of regressors with a constant, and an vector of the dependent variable. Following Koenker (2005) we can write the quantile problem as a linear problem, Recall that the primal problem in a linear program can be written as. To translate this problem into Rmosek it is useful to make the following correspondences: where is an n-vector of ones. furthermore, note that and that in. Create the Corpus and Document Term Matrix. The first thing we need to do is import the csv file into a corpus using the tm package. The corpus will be used to construct the document term matrix for use in developing the topic model. Since I am importing a spreadsheet, I need to create a mapping for the corpus to use. The first item is the content used in the modeling, the remaining items are. Matrix properties There are a few useful functions that return basic properties of matrices dim() returns the number of rows and columns det() returns the determinant of a square matrix diag() returns the diagonal entries of a matrix OR turns a vectors into a diagonal matrix. An R introduction to statistics. Explain basic R concepts, and illustrate with statistics textbook homework exercise. R - Matrices. Advertisements. Previous Page. Next Page. Matrices are the R objects in which the elements are arranged in a two-dimensional rectangular layout. They contain elements of the same atomic types. Though we can create a matrix containing only characters or only logical values, they are not of much use. We use matrices containing numeric elements to be used in mathematical. Ideas surrounding tidy evaluation quote() and eval() Why quote at-all Resolved messy data with tidy evaluation List behavior Using pmap to perform list operations inside a dataframe Apply a function to certain columns only, by rows Do any arbitrary operation Using dplyr functions inside your own functions Effiecient ways to operate on list Binds each element as row but third element is list. The sizes of the input arguments must be compatible. For example, if the first input is a matrix of size 3-by-2, then B must have 3 rows. All table inputs must have unique variable names. When present, row names must be identical, except for order. All timetable inputs must have the same row times and all columns must have different names. You can concatenate valid combinations of different. Adding a series of new observations using rbind. If you need to add multiple new observations to a data frame, doing it one-by-one is not entirely practical. Luckily, you can use rbind() to attach a matrix or a data frame with new observations to the original data frame. The matching of the columns is done by name, so you need to make sure that. Details. If X is not an array but an object of a class with a non-null dim value (such as a data frame), apply attempts to coerce it to an array via as.matrix if it is two-dimensional (e.g., a data frame) or via as.array. FUN is found by a call to match.fun and typically is either a function or a symbol (e.g., a backquoted name) or a character string specifying a function to be searched for. R Programming: Quiz1 Raw. rprog-quiz1.txt 1: The R language is a dialect of which of the following programming languages? S: 2: The definition of free software consists of four freedoms (freedoms 0 through 3). Which of the following is NOT one of the freedoms that are part of the definition? The freedom to prevent users from using the software for undesirable purposes. 3: In R the following. Portfolio Theory with Matrix Algebra Updated: August 7, 2013 When working with large portfolios, the algebra of representing portfolio expected returns and variances becomes cumbersome. The use of matrix (lin-ear) algebra can greatly simplify many of the computations. Matrix algebra formulations are also very useful when it comes time to do actual computa-tions on the computer. The matrix.

## Data Types - Matrices - Week 1: Background, Getting.

This tutorial explains how to write loop in R. It includes explanation of. Sapply is a user friendly version of Lapply as it returns a vector when we apply a function to each element of a data structure. Example 1: Number of Missing Values in each Variable sapply(dat, function(x) sum(is.na(x))) The above function returns 1,1,0 for variables x,z,y in data frame 'dat'. Example 2: Extract.

From ?as.data.matrix: Return the matrix obtained by converting all the variables in a data frame to numeric mode and then binding them together as the columns of a matrix. Factors and ordered factors are replaced by their internal codes. data.matrix() returns a numeric matrix, where characters are replace by missing values.