CODEWITHSUNDEEP
r
mtkilic
mtkilic

Reputation: 1243

Count the number of duplicated values

I am trying to run function that will take one parameter, which is list of numbers, and count the duplicates.

Example:

number <- c(1, 1, 1, 2, 2, 4, 5)

In this case, the output will be 2, because only 1 and 2 have duplicates.

I know how to use for loop but not sure how to count duplicates.

count = 0
for (x in number){
    ...
}

Upvotes: 1

Views: 1206

Answers (2)

user7585900
user7585900

Reputation:

This solution is written in Python.

import collections
number = [1,1,1,2,2,4,5]
x = collections.Counter(number)
len([i for i in x if x[i]>1])

It puts the numbers that appears more than once in a list and then counts how many elements are in that list.

Upvotes: 0

Rich Scriven
Rich Scriven

Reputation: 99371

Tabulate the values, then count how many of those are greater than one.

x <- c(1, 1, 1, 2, 2, 4, 5)

sum(tabulate(x) > 1)
# [1] 2

Or, if you're looking for straight runs of duplicates, rle can be used as an alternative to tabulation.

with(rle(x), sum(lengths > 1))
# [1] 2

Upvotes: 4

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