![]() ![]() Summary(survey_vector) # Length Class Mode # Notice how summary treats a factor variable different from a regular variable. Levels(factor_survey_vector) <- c("Female", "Male") Survey_vector <- c("M", "F", "F", "M", "M")įactor_survey_vector <- factor(survey_vector) Note the levels are initially in alphabetical order. student_status temperature_vector # FALSE factor_temperature_vector > factor_temperature_vector # TRUE # Change the level names with the levels function. To specify an ordinal categorical variable, specify order = TRUE and levels. R needs to know whether a variable is continuous or categorical. The factor() function converts a variable into type factor. # "On row 5 and column 4 the matrix contains 20" # "On row 5 and column 3 the matrix contains 19" # "On row 5 and column 2 the matrix contains 18" # "On row 5 and column 1 the matrix contains 17" # "On row 4 and column 4 the matrix contains 16" ![]() # "On row 4 and column 3 the matrix contains 15" # "On row 4 and column 2 the matrix contains 14" # "On row 4 and column 1 the matrix contains 13" # "On row 3 and column 4 the matrix contains 12" # "On row 3 and column 3 the matrix contains 11" # "On row 3 and column 2 the matrix contains 10" # "On row 3 and column 1 the matrix contains 9" # "On row 2 and column 4 the matrix contains 8" # "On row 2 and column 3 the matrix contains 7" # "On row 2 and column 2 the matrix contains 6" # "On row 2 and column 1 the matrix contains 5" # "On row 1 and column 4 the matrix contains 4" # "On row 1 and column 3 the matrix contains 3" # "On row 1 and column 2 the matrix contains 2" for (i in 1:nrow(m)) # "On row 1 and column 1 the matrix contains 1" Use nrows() and ncols() to determine number of rows and columns. # row 5 17 18 19 20 74 # All rows of the second colum of m. # row 5 17 18 19 20 # Bind row sums to matrix.Ĭbind(m, m.rowSum) # Col 1 col 2 col 3 col 4 m.rowSum M <- matrix(1:20, byrow = TRUE, nrow = 5, ncol = 4) Specifying the number of columns is optional if number of rows is specified. # Matrix of numbers 1:20, filling one row at a time, for 5 rows and 4 columns. Bind rows and columns to a matrix with rbind() and cbind(). Sum each row and column into vectors with rowSums() and colSums(). Label the rows with rownames() and the columns with colnames(). Create a matrix with the matrix(data, nrow, ncol, byrow) function. For example, a 0] # Wednesday FridayĪ matrix is a two-dimensional collection of elements. Subset a list with single brackets and extract elements with double brackets. Vectors have two key properties: type typeof() of length length(). Lists are recursive vectors (they can contain other lists). Atomic vectors are homogenous of one of six types: logical, integer, double, character, complex, and raw (don’t worry about the relatively uncommon complex and raw types). There are two types of vectors in R: atomic vectors, and lists. If you compare a vector to a singe value, R will create an appropriately sized vector. Reference vector elements with brackets, or with element names. sub and a values should be preserved (their positions and values) for a proper functioning.Create a vector with the combine function c(). The need for L=a.size() should've been a hint. Var res = b.CartesianProduct().Select( x => string.Join( ",", x ) ) Īnd we're done! List all permutations & combinations in Integer Arraylist recursively Then we can simply do: var a = "1|2,3|4".Split( ',' ) There are two steps - create an array list pairs of each operator and its reverse and then recursively permute these together. This turned out to be harder than it looks, but the following should demonstrate the idea. ![]()
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