source is available in the file menu. Today R runs on almost any standard computing platform and operating system. Its open source nature. The copyright for the primary source code for R is held by the R Foundation and is published under the GNU General Public License version.
4. Advanced programmers can write ______ code to manipulate R objects.
There are base packages (which come with R automatically), and contributed packages. The base packages are maintained by a select group of volunteers called R Core. In addition to the base packages, there are over ten thousand additional contributed packages written by individuals all over the world.
Factors are used to represent categorical data and can unordered and ordered. One can think of a factor as an integer vector where each integer has a label. Factors are important in statistical modelling and are treated specially by modelling functions like lm() and glm().
When you have multiple processors/- cores/machines working in parallel, the amount of time that the collection of CPUs spends working on a problem is the same as with a single CPU, but because they are operating in parallel, there is a savings in elapsed time.
Predicting y for a value of x that is within the interval of points that we saw in the original data is called interpolation. Predicting y for a value of x that’s outside the range of values we actually saw for x in the original data is called extrapolati
Single element of a character vector is often referred to as a character string. Dates are represented by the Date class and can be coerced from a character string using the as.Date() function. This is a common way to end up with a Date object in R.
sqldf uses SQLite syntax. Plyr will split-apply-combine paradigm for R. Forecast is a generic function for forecasting from time series or time series models. The function invokes particular methods which depend on the class of the first argument.
A data frame is a very important data type in R. It’s pretty much the de facto data structure for most tabular data and what we use for statistics. A data frame was a special type of list in which every element of the list has the same length.
The factor stores the nominal values as a vector of integers in the range [1… k] (where k is the no. of unique values of the nominal variable), and an internal vector of character strings (the original values) mapped to these integers.
The distr package has a functionality to find the transformations of one variable distribution. There are exact results for the ordinary transformations for the standard distributions, and distr takes advantage of these in many cases.
