Looking for the most important functions in R? This blog post answers key questions like creating frequency tables (table()), redirecting output (sink()), transposing data, calculating standard deviation, performing t-tests, ANOVA, and more. Perfect for R beginners and data analysts!
- Important functions in R
- R programming cheat sheet
- Frequency table in R (
table()) - How to use
sink()in R - Transpose data in R (
t()) - Standard deviation in R (
sd()) - T-test, ANOVA, and Shapiro-Wilk test in R
- Correlation and covariance in R
- Scatterplot matrices (
pairs()) - Diagnostic plots in R
This Important functions in R, Q&A-style guide covers essential R functions with clear examples, helping you master data manipulation, statistical tests, and visualization in R. Whether you’re a beginner or an intermediate user, this post will strengthen your R programming skills!
Table of Contents
Which function is used to create a frequency table in R?
In R, a frequency table can be created by using table() function.
What is the use of sink() function?
The sink() function in R is used to redirect R output (such as the results of computations, printed messages, or console output) to a file instead of displaying it in the console. This is particularly useful for saving logs, results of analyses, or any other text output generated by R scripts.
Explain what transpose is and how it is performed.
Transpose is used for reshaping the data, which is used for analysis. Transpose is performed by t() function.
What is the length function in R?
The length() function in R gets or sets the length of a vector (list) or other objects. The length() function can be used for all R objects. For an environment, it returns the object number in it. NULL returns 0.
What is the difference between seq(4) and seq_along(4)?
seq(4) means vector from 1 to 4 (c(1,2,3,4)) whereas seq_along(4) means a vector of the length(4) or 1 (c(1)).
Vector $v$ is c(1,2,3,4) and list $x$ is list(5:8). What is the output of v*x[[1]]?
[1] 5 12 21 32s
How do you get the standard deviation for a vector $x$?
sd(x, na.rm=TRUE)
$X$ is the vector c(5,9.2,3,8.51,NA). What is the output of mean(x)?
The output will be NA.
How can one compute correlation and covariance in R?
Correlation is produced by cor() and covariance is produced by cov() function.
How to create scatterplot matrices?
pair() or splom() function are used to create scatterplot matrices.
What is the use of diagnostic plots?
It is used to check the normality, heteroscedasticity, and influential observations.
What is principal() function?
It is defined in the psych package that is used to rotate and extract the principal components.
Define mshapiro.test()?
It is a function which defined in the mvnormtest package. It produces the Shapiro-Wilk test for multivariate normality.
Define barlett.test().
The barlett.test() is used to provide a parametric k-sample test of the equality of variances.
Define anova() function.
The anova() is used to compare the nested models. Read more One-Way ANOVA
Define plotmeans().
It is defined under the gplots package, which includes confidence intervals, and it produces a mean plot for single factors.
Define loglm() function.
The loglm() function is used to create log-linear models.
What is t-tests() in R?
We use it to determine whether the means of two groups are equal or not by using t.test() function.