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Questions tagged [combn]

121 questions
19
votes
5 answers

Faster version of combn

Is there a way to speed up the combn command to get all unique combinations of 2 elements taken from a vector? Usually this would be set up like this: # Get latest version of data.table library(devtools) install_github("Rdatatable/data.table", …
majom
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3 answers

Find all possible teams in R

Feels like this should be straightforward but I have been through stack overflow and combn help, and cannot see solution. The below players need to be in teams of 3 versus 2. I need to find all possible combinations of teams. For example two…
luciano
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12
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3 answers

Intersect all possible combinations of list elements

I have a list of vectors: > l <- list(A=c("one", "two", "three", "four"), B=c("one", "two"), C=c("two", "four", "five", "six"), D=c("six", "seven")) > l $A [1] "one" "two" "three" "four" $B [1] "one" "two" $C [1] "two" "four" "five"…
enricoferrero
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7
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3 answers

Generate all unique combinations from a vector with repeating elements

This questions was asked previously but only for vectors with non-repeating elements. I was not able to find an easy solution to get all combinations from a vector with repeating elements. To illustrate I listed an example below. x <- c('red',…
Jian
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6
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3 answers

R: how to perform more complex calculations from a combn of a dataset?

Right now, I have a combn from the built in dataset iris. So far, I have been guided into being able to find the coefficient of lm() of the pair of values. myPairs <- combn(names(iris[1:4]), 2) formula <- apply(myPairs, MARGIN=2, FUN=paste,…
Luke Zhang
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6
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1 answer

Get all possible combinations by row in matrix

I have an m x n matrix that looks like this: 1 2 3 4 5 6 What is the fastest way to get all possible combinations by row? In this case, that would be c(1,4), c(1,5), c(1,6), c(2,4), c(2,5) ... c(3,5), c(3,6) How do I solve this using a vectorized…
user3294195
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5
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Efficiently find the overlap between two time intervals in R

I have used combn() to find the overlap between two dates/times using lubridate package. But combn() is too slow to process the large dataset I am working on. I am trying to use comboGeneral() from RcppAlgos package but I can't get it to work. Any…
Zaw
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5
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3 answers

R find all possible unique combinations

I am trying to find all possible unique combinations in R. It seems that there have been a lot of similar questions asked, but I was not able to find the same one. My question is to find combinations of m number of elements from vector x, but m…
Jian
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5
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2 answers

Find all the sums of all combinations of 3 rows from 5 columns

I've loaded a table from a .CVS file using mydata = read.csv("CS2Data.csv") # read csv file which gave me: mydata Date DCM TMUS SKM RCI SPOK 1 11/2/2015 -0.88 -2.16 -1.04 1.12 0.67 2 12/1/2015 1.03 3.26 -2.25 -5.51 -0.23 3 …
JimJ
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5
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3 answers

Possible combinations of a vector with respect order

x <- letters[1:4] x # [1] "a" "b" "c" "d" t(combn(x, 2)) # [,1] [,2] # [1,] "a" "b" # [2,] "a" "c" # [3,] "a" "d" # [4,] "b" "c" # [5,] "b" "d" # [6,] "c" "d" How should I write the code if I also what inverse combinations with b-a,…
Tomas Ericsson
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4
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2 answers

Calculating combinations of column names without duplicates using combn

I have two dataframes with 3 columns each and each dataframe consists of different data types (df1 has continuous data with column name suffix "con", df2 has categorical data with column name suffix "cat") My data: df1 <- data.frame(t1_con=c(1:5),…
LHordley
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4
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3 answers

Convert combn output to matrix of type 'dist'

I have a dataframe in the following form: dim1 dim2 1 Loc.1 0.325 2 Loc.2 0.325 3 Loc.3 0.321 4 Loc.4 0.256 5 Loc.5 0.255 I would like to compute the mean of each combination of two (2) elements within 'dim2'; and convert the output into a…
Chrys
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Duplicating & modifying rows of a dataframe dependent on observations [R]

This is a follow up to this question: Duplicating observations of a dataframe, but also replacing specific variable values in R I have tried to write as succinctly as possible, whilst giving all necessary information. In this current example, I…
jalapic
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2 answers

Use data.table in R to add multiple columns to a data.table with = with only one function call

This is a direkt expansion of this Question. I have a dataset and I want to find all pairwise combinations of Variable v depending on Variables x and y: library(data.table) DT = data.table(x=rep(c("a","b","c"),each=6), y=c(1,1,6), v=1:18) x…
fc9.30
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6 answers

All Combinations of Numbers That Meet a Condition

I am working with the R programming language. Suppose I have numbers: 2010,2011,2012,2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 My Question: I want to find out all possible pairs of these numbers where the difference is greater than 1. E.g.…
stats_noob
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