For columns classx get or set the class of x classx

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Unformatted text preview: as) Variable information is.na(x), is.null(x), is.array(x), is.data.frame(x), is.numeric(x), is.complex(x), is.character(x), ... test for type; for a complete list, use methods(is) length(x) number of elements in x dim(x) Retrieve or set the dimension of an object; dim(x) <- c(3,2) dimnames(x) Retrieve or set the dimension names of an object nrow(x) number of rows; NROW(x) is the same but treats a vector as a onerow matrix ncol(x) and NCOL(x) id. for columns class(x) get or set the class of x; class(x) <- "myclass" unclass(x) remove the class attribute of x attr(x,which) get or set the attribute which of x attributes(obj) get or set the list of attributes of obj Data selection and manipulation which.max(x) returns the index of the greatest element of x which.min(x) returns the index of the smallest element of x rev(x) reverses the elements of x sort(x) sorts the elements of x in increasing order; to sort in decreasing order: rev(sort(x)) cut(x,breaks) divides x into intervals (factors); breaks is the number of cut intervals or a vector of cut points match(x, y) returns a vector of the same length than x with the elements of x which are in y (NA otherwise) which(x == a) returns a vector of the indices of x if the comparison operation is true (TRUE), in this example the values of i for which x[i] == a (the argument of this function must be a variable of mode logical) choose(n, k) computes the combinations of k events among n repetitions = n!/[(n − k)!k!] na.omit(x) suppresses the observations with missing data (NA) (suppresses the corresponding line if x is a matrix or a data frame) na.fail(x) returns an error message if x contains at least one NA unique(x) if x is a vector or a data frame, returns a similar object but with the duplicate elements suppressed table(x) returns a table with the numbers of the differents values of x (typically for integers or factors) subset(x, ...) returns a selection of x with respect to criteria (..., typically comparisons: x$V1 < 10); if x is a data frame, the option select gives the variables to be kept or dropped using a minus sign sample(x, size) resample randomly and without replacement size elements in the vector x, the option replace = TRUE allows to resample with replacement prop.table(x,margin=) table entries as fraction of marginal table Math sin,cos,tan,asin,acos,atan,atan2,log,log10,exp max(x) maximum of the elements of x min(x) minimum of the elements of x range(x) id. then c(min(x), max(x)) sum(x) sum of the elements of x diff(x) lagged and iterated differences of vector x prod(x) product of the elements of x mean(x) mean of the elements of x median(x) median of the elements of x quantile(x,probs=) sample quantiles corresponding to the given probabilities (defaults to 0,.25,.5,.75,1) weighted.mean(x, w) mean of x with weights w rank(x) ranks of the elements of x var(x) or cov(x) variance of the elements of x (calculated on n − 1); if x is a matrix or a data frame, the variance-covariance matrix is calculated sd(x) standard deviation of x cor(x) correlation matrix of x if it is a matrix or a data frame (1 if x is a vector) var(x, y) or cov(x, y) covariance between x...
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This document was uploaded on 04/10/2014.

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