R Programming Language was built for Statistics and data analysis which means it has many functions available for this purpose. The function which were already defined in the programming framework. R has a set of function which can be used to perform almost every task for the users.
String Function
Function | Description |
substr(x, start=n1,stop=n2) | It is used to extract or replace substrings in a character vector. |
grep(pattern, x , ignore.case=FALSE, fixed=FALSE) | It is used for searching for pattern in x. |
sub(pattern, replacement, x, ignore.case =FALSE, fixed=FALSE) | It is used for finding pattern in x and replaces it with replacement text. |
paste(..., sep="") | It is used for concatenation of strings after using sep string to separate them. |
strsplit(x, split) | It is used for splitting the elements of character vector at splitting points. |
tolower(x) | It is used to convert strings to lower case. |
topper(x) | It is used to convert strings to upper case. |
Numeric Functions
Functions | Description |
abs(x) | It is used to return the absolute value of x. |
sqrt(x) | It returns the square root of the x. |
ceiling(x) | It returns the smallest integer value which is larger than or equal to x. |
floor(x) | It returns the largest integer value which is smaller than or equal to x. |
trunc(x) | It is used for performing truncate of the value x. |
round(x, digits=n) | It returns the round value of x. |
cos(x), sin(x), tan(x) | It is used to return the cos ,sin or tan values of x. |
log(x) | It gives natural logarithm. |
log10(x) | It gives the common logarithm. |
exp(x) | It returns exponent. |
Statistical Probability Functions
Function | Description |
dnorm(x, m=0, sd=1, log=False) | It is used for finding the height at each point to a given mean and standard deviation of a probability distribution. |
pnorm(q, m=0, sd=1, lower.tail=TRUE, log.p=FALSE) | It is used to find cumulative normal probability for q |
qnorm(p, m=0, sd=1) | It is used to find a number whose cumulative value is same as the probability value. |
rnorm(n, m=0, sd=1) | It is used to generate random numbers with normal distribution. |
dbinom(x, size, prob) | It return the probability density distribution at each point. |
pbinom(q, size, prob) | It return the cumulative value whose probability value is same. |
rbinom(n, size, prob) | It return numbers of random values of a given probability from a given sample. |
dpois(x, lamba) | It is used to find the probability of x successes in a period when the expected number of events is lambda. |
ppois(q, lamba) | It is used to find cumulative probability of less than or equal to q successes. |
rpois(n, lamba) | It return random numbers from the poisson distribution. |
dunif(x, min=0, max=1) | It provide information about the uniform distribution on the interval from min to max. It gives the density. |
punif(q, min=0, max=1) | It return the distributed function |
qunif(p, min=0, max=1) | It return the quantile function |
runif(x, min=0, max=1) | It generates random deviates |
Other Statistical Function
Function | Description |
mean(x, trim=0, na.rm=FALSE) | It return the mean for x. |
sd(x) | It return the standard deviation of the object. |
median(x) | It return the median for x |
quantilie(x, probs) | It return quantile where x is the numeric vector whose quantile are desired and prob is a numeric vector with probabilities in [0,1] |
range(x) | It return range. |
sum(x) | It return sum. |
diff(x, lag=1) | It return lagged differences, with lag indicating which lag to use. |
min(x) | It return minimum value. |
max(x) | It return maximum value. |
scale(x, center=TRUE, scale=TRUE) | It is used to standardize a matrix. |