rowMins: Returns the min value of each row of a data.frame or matrix

In ejanalysis/analyze.stuff: Miscellaneous Tools for Analyzing Data in Rows and Columns

Returns the min value of each row of a data.frame or matrix

Description

Returns minimum value of each row of a data.frame or matrix.

Usage

rowMins(df, na.rm = TRUE)

Arguments

df	Data.frame or matrix, required.
na.rm	Logical value, optional, TRUE by default. Defines whether NA values should be removed first. Otherwise result will be NA when any NA is in the given vector.

Details

** NOTE: The useful matrixStats package is the basis for versions of rowMins, rowMax, colMins, colMaxs functions in this package. Source: Henrik Bengtsson (2015). matrixStats: Methods that Apply to Rows and Columns of a Matrix. R package version 0.13.1-9000.

https://github.com/HenrikBengtsson/matrixStats

Initially, separate functions were written here for those four functions, and the versions here were more flexible and convenient for some purposes, e.g., handling data.frames and different na.rm defaults, but the matrixStats versions are much faster (e.g., by 4x or more). Ideally, this analyze.stuff package would be modified to just extend those functions by providing them methods to handle data.frames, not just matrix class objects, and perhaps provide new or different parameters or defaults, such as defaulting to na.rm=TRUE instead of FALSE, and handling factor class columns in a data.frame. That has not been done yet, so colMaxs() etc. refer to the slower more flexible ones, and the faster matrix-only ones are via matrixStats::colMaxs etc.

** NOTE: max() and min() and matrixStats::colMaxs() from matrixStats etc. default to na.rm=FALSE, but this function defaults to na.rm=TRUE because that just seems more frequently useful.

** NOTE: min and max & this function will handle character elements by coercing all others in the column to character, which can be confusing – e.g., note that min(c(8,10,'txt')) returns '10' not '8' and max returns 'txt' (also see the help for ?Comparison )

If this worked just like max() and min(), cols that are factors would make this fail. max or min of a factor fails, even if as.character() of the factor would return a valid numeric vector. That isn't an issue with a matrix, but a data.frame might have numbers stored as factor. To fix that, this uses factor.as.numeric with parameters that try to convert character or factor columns to numeric. Based on how min() and max() behave, return Inf or -Inf if no non-missing arguments to min or max respectively. To suppress that warning when using this function, use suppressWarnings()

Value

Returns a vector of numbers of length equal to number of rows in df.

See Also

factor.as.numeric() rowMaxs() rowMins() colMaxs() colMins() count.above() pct.above() pct.below() cols.above.which() cols.above.pct()

Examples

blah <- rbind(NA, data.frame(a=c(0, 0:8), b=c(0.1+(0:9)), c=c(1:10), d=c(rep(NA, 10)),
  e=TRUE, f=factor('factor'), g='words', stringsAsFactors=FALSE) )
cbind(blah, min=rowMins(blah), max=rowMaxs(blah))
## note that colMaxs(blah) was failing if any of the columns were not numeric
##  rbind(blah, min = analyze.stuff::colMins(blah), max= analyze.stuff::colMaxs(blah))

blah <- blah[ , sapply(blah, function(x) is.numeric(x) | is.logical(x)) ]
cbind(blah, min=rowMins(blah), max=rowMaxs(blah),
  mean=rowMeans(blah, na.rm=TRUE), sum=rowSums(blah, na.rm=TRUE))
rbind(blah, min=colMins(blah), max=colMaxs(blah),
  mean=colMeans(blah, na.rm=TRUE), sum=colSums(blah, na.rm=TRUE))
  # ** Actually, matrixStats does this ~4x as quickly,
  # although no practical difference unless large dataset:
  n <- 1e7
t1=Sys.time(); x=analyze.stuff::colMaxs( cbind(a=1:n, b=2, c=3, d=4, e=5)); t2=Sys.time()
print(difftime(t2,t1))
t1=Sys.time(); x=  matrixStats::colMaxs( cbind(a=1:n, b=2, c=3, d=4, e=5)); t2=Sys.time()
print(difftime(t2,t1))
# Note the latter cannot handle a data.frame:
## Not run: 
# This would fail:
matrixStats::colMaxs(   data.frame(a=1:10, b=2))
# This works:
analyze.stuff::colMaxs( data.frame(a=1:10, b=2))

## End(Not run)

ejanalysis/analyze.stuff documentation built on April 2, 2024, 10:10 a.m.