DataFrame-utils: Common operations on DataFrame objects

Description Merging Splitting Looping Subsetting based on NA content Transforming Statistical modeling with DataFrame Author(s) See Also Examples

Description

Common operations on DataFrame objects.

Merging

In the code snippet below, x is a DataFrame object.

merge(x, y, ...): Merges two DataFrame objects x and y, with arguments in ... being the same as those allowed by the base merge. It is allowed for either x or y to be a data.frame.

Splitting

In the code snippet below, x is a DataFrame object.

split(x, f, drop = FALSE): Splits x into a SplitDataFrameList object, according to f, dropping elements corresponding to unrepresented levels if drop is TRUE.

Looping

In the code snippet below, x is a DataFrame object.

by(data, INDICES, FUN, ..., simplify = TRUE): Apply FUN to each group of data, a DataFrame, formed by the factor (or list of factors) INDICES. Exactly the same contract as as.data.frame.

Subsetting based on NA content

In the code snippets below, x is a DataFrame object.

na.omit(object): Returns a subset with incomplete cases removed.

na.exclude(object): Returns a subset with incomplete cases removed (but to be included with NAs in statistical results).

is.na(x): Returns a logical matrix indicating which cells are missing.

complete.cases(x): Returns a logical vector identifying which cases have no missing values.

Transforming

In the code snippet below, x is a DataFrame object.

transform(`_data`, ...): adds or replaces columns based on expressions in .... See transform.

Statistical modeling with DataFrame

A number of wrappers are implemented for performing statistical procedures, such as model fitting, with DataFrame objects.

Tabulation

xtabs(formula = ~., data, subset, na.action, exclude = c(NA, NaN), drop.unused.levels = FALSE): Like the original xtabs, except data is a DataFrame.

Author(s)

Michael Lawrence

See Also

Examples

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## split
sw <- DataFrame(swiss)
swsplit <- split(sw, sw[["Education"]])

## rbind & cbind
do.call(rbind, as.list(swsplit))
cbind(DataFrame(score), DataFrame(counts))

df <- DataFrame(as.data.frame(UCBAdmissions))
xtabs(Freq ~ Gender + Admit, df)

S4Vectors documentation built on Dec. 11, 2020, 2:02 a.m.