nameVectorN: define a named vector using vector names
In jmw86069/jamba: Jam Base Methods

nameVectorN

R Documentation

define a named vector using vector names

Description

define a named vector using vector names

Usage

nameVectorN(x, makeNamesFunc = makeNames, ...)

Arguments

`x`	vector or any object which has names available via `names(x)`
`makeNamesFunc`	function used to create unique names, in the event that the names(x) are not unique.

Details

This function creates a vector from the names of the input vector, then assigns the same as names. The utility is mainly for lapply functions which maintain the name of a vector in its output. The reason to run lapply using names is so the lapply function is operating only on the name and not the data it references, which can be convenient when the name of the element is useful to known inside the function body. The reason to name the names, is so the list object returned by lapply is also named with these same consistent names.

Consider a list of data.frames, each of which represents stats results from a contrast and fold change. The data.frame may not indicate the name of the contrast, while the list itself may be named by the contrast. One would lapply(nameVectorN(listDF), function(iName)iName) which allows the internal function access to the name of each list element. This could for example be added to the data.frame.

Value

vector of names, whose names are uniquely assigned using makeNames using the values of the vector.

Examples

# a simple integer vector with character names
L <- nameVector(1:5, LETTERS[1:5]);
L;

# we can make a vector of names, retaining the names
nameVectorN(L);

# Now consider a named list, where the name is important
# to keep for downstream work.
K <- list(A=(1:3)^3, B=7:10, C=(1:4)^2);
K;
# Typical lapply-style work does not operate on the name,
# making it difficult to use the name inside the function.
# Here, we just add the name to the colnames, but anything
# could be useful.
lapply(K, function(i){
    data.frame(mean=mean(i), median=median(i));
 });

# So the next step is to run lapply() on the names
lapply(names(K), function(i){
   iDF <- data.frame(mean=mean(K[[i]]), median=median(K[[i]]));
   colnames(iDF) <- paste(c("mean", "median"), i);
   iDF;
})
# The result is good, but the list is no longer named.
# The nameVectorN() function is helpful for maintaining the names.

# So we run lapply() on the named-names, which keeps the names in
# the resulting list, and sends it into the function.
lapply(nameVectorN(K), function(i){
   iDF <- data.frame(mean=mean(K[[i]]), median=median(K[[i]]));
   colnames(iDF) <- paste(c("mean", "median"), i);
   iDF;
});

jmw86069/jamba documentation built on Oct. 9, 2024, 10:52 a.m.