## Counting the number of elements with the values of x in a vector

I have a vector of numbers:

numbers <- c(4,23,4,23,5,43,54,56,657,67,67,435, 453,435,324,34,456,56,567,65,34,435)

How can I have R count the number of times a value *x* appears in the vector?

You can just use `table()`

:

> a <- table(numbers) > a numbers 4 5 23 34 43 54 56 65 67 324 435 453 456 567 657 2 1 2 2 1 1 2 1 2 1 3 1 1 1 1

Then you can subset it:

> a[names(a)==435] 435 3

Or convert it into a data.frame if you're more comfortable working with that:

> as.data.frame(table(numbers)) numbers Freq 1 4 2 2 5 1 3 23 2 4 34 2 ...

**R Is Not So Hard! A Tutorial, Part 15: Counting Elements in a Data Set,** In fact, you can count the number of elements that satisfy almost any given condition. perc <- function(x, n){ 100*length((which(x == n))) / length(x) }. Note the syntax involved in setting up a function in R. Now let's use the count function to count the threes in the vector b. A Tutorial, Part 16: Counting Values within Cases R count the number of times a value x appears in the vector? Login. Remember. Register; Counting the number of elements with the values of x in a vector. 0 votes

The most direct way is `sum(numbers == x)`

.

`numbers == x`

creates a logical vector which is TRUE at every location that x occurs, and when `sum`

ing, the logical vector is coerced to numeric which converts TRUE to 1 and FALSE to 0.

However, note that for floating point numbers it's better to use something like: `sum(abs(numbers - x) < 1e-6)`

.

**Length of an Object,** x. an R object. For replacement, a vector or factor. value. a non-negative integer or double If a vector is shortened, extra values are discarded and when a vector is For vectors (including lists) and factors the length is the number of elements. nchar for counting the number of characters in character vectors, lengths for In this way, I can determine the number of elements in a vector that are above or below a certain number, like so. > sum(v > 2) [1] 3 > sum(v < 2) [1] 1 Does anyone know how I can determine the number of values in a given range? For example, how would I determine the number of values greater than 2 but less than 5?

I would probably do something like this

length(which(numbers==x))

But really, a better way is

table(numbers)

**The advantages of using count() to get N-way ,** in the “plyr” package to get the same frequencies in a list format. Count observations greater than a particular value [duplicate] How many elements in a vector are greater than x Counting the number of elements with the

There is also `count(numbers)`

from `plyr`

package. Much more convenient than `table`

in my opinion.

**R Frequency of Elements with Certain Value,** How to count the number of elements with a given value in a vector - 2 R set.seed(98765) # Set seed x <- round(rnorm(1000)) # Create vector with random Our example vector consists of 1,000 normally distributed numeric values. std::count () returns number of occurrences of an element in a given range. Returns the number of elements in the range [first,last) that compare equal to val. // Returns count of occurrences of value in. // range [begin, end] int count (Iterator first, Iterator last, T &val) first, last : Input iterators to the initial and final positions of

My preferred solution uses `rle`

, which will return a value (the label, `x`

in your example) and a length, which represents how many times that value appeared in sequence.

By combining `rle`

with `sort`

, you have an extremely fast way to count the number of times any value appeared. This can be helpful with more complex problems.

Example:

> numbers <- c(4,23,4,23,5,43,54,56,657,67,67,435,453,435,324,34,456,56,567,65,34,435) > a <- rle(sort(numbers)) > a Run Length Encoding lengths: int [1:15] 2 1 2 2 1 1 2 1 2 1 ... values : num [1:15] 4 5 23 34 43 54 56 65 67 324 ...

If the value you want doesn't show up, or you need to store that value for later, make `a`

a `data.frame`

.

> b <- data.frame(number=a$values, n=a$lengths) > b values n 1 4 2 2 5 1 3 23 2 4 34 2 5 43 1 6 54 1 7 56 2 8 65 1 9 67 2 10 324 1 11 435 3 12 453 1 13 456 1 14 567 1 15 657 1

I find it is rare that I want to know the frequency of one value and not all of the values, and rle seems to be the quickest way to get count and store them all.

**Count number of specific values in matrix,** I have a large matrix, m, and am trying to count the number of a specific value (i.e. but I end up with val being a matrix/vector of numbers. uv = unique(x);. As of MATLAB R2019a, you can use the “groupcounts” function to compute the number of times an element appears in a vector as a summary. In other words, the elements of the below output “GC” are the counts of the corresponding element values in “GR” (from the original input vector “x”): x = [10 25 4 10 9 4 4]';

**How can I count the occurrences of each element in a vector in ,** Learn more about unique, occurences, repetitions, count, histogram MATLAB. to compute the number of times an element appears in a vector as a summary. of the corresponding element values in “GR” (from the original input vector “x”):. I'm looking for a way to count the frequency of each element in a vector. ex <- c(2,2,2,3,4,5) Desired outcome: [1] 3 3 3 1 1 1 Is there a simple command for this?

**count function,** Equivalent to as.data.frame(table(x)) , but does not include combinations with zero Count the number of occurences. variables to count unique values of. If A is a table, numel returns the number of elements in the table, A, equivalent to prod (size (A)). Variables in a table can have multiple columns, but numel (A) only accounts for the number of rows and number of variables. If A is a character vector of type char, then numel returns the number of characters.

**length function,** x. an R object. For replacement, a vector or factor. value. a non-negative integer or For vectors (including lists) and factors the length is the number of elements. and that return a vector of type double (Matrix), even with non-integer values nchar for counting the number of characters in character vectors, lengths for by David Lillis, Ph.D. Combining the length () and which () commands gives a handy method of counting elements that meet particular criteria. Let’s count the 3s in the vector b. In fact, you can count the number of elements that satisfy almost any given condition. Here is an alternative approach, also using the length () command, but also