Multivariate computation.
Easily compute multivariate sum, mean, and other scores.
Reverse scoring can also be easily implemented without saving extra variables.
Alpha
function uses a similar method to deal with reverse scoring.
Three options to specify the variable list:
var + items
: use the common and unique parts of variable names.
vars
: directly define a variable list.
varrange
: use the start and end positions of a variable list.
COUNT(data, var = NULL, items = NULL, vars = NULL, varrange = NULL, value = NA) MODE(data, var = NULL, items = NULL, vars = NULL, varrange = NULL) SUM( data, var = NULL, items = NULL, vars = NULL, varrange = NULL, rev = NULL, likert = NULL, na.rm = TRUE ) MEAN( data, var = NULL, items = NULL, vars = NULL, varrange = NULL, rev = NULL, likert = NULL, na.rm = TRUE ) STD( data, var = NULL, items = NULL, vars = NULL, varrange = NULL, rev = NULL, likert = NULL, na.rm = TRUE ) CONSEC( data, var = NULL, items = NULL, vars = NULL, varrange = NULL, values = 0:9 )
data |
Data frame. |
var |
[option 1]
Common part across multiple variables (e.g., |
items |
[option 1]
Unique part across multiple variables (e.g., |
vars |
[option 2]
Character vector specifying a variable list (e.g., |
varrange |
[option 3]
Character with |
value |
[only for |
rev |
[optional] Reverse-scoring variables. It can be (1) a numeric vector specifying the positions of reverse-scoring variables (not recommended) or (2) a character vector directly specifying the variable list (recommended). |
likert |
[optional] Range of likert scale (e.g., |
na.rm |
Ignore missing values. Default is |
values |
[only for |
A vector of computed values.
COUNT
: Count a certain value across multiple variables.
MODE
: Compute mode across multiple variables.
SUM
: Compute sum across multiple variables.
MEAN
: Compute mean across multiple variables.
STD
: Compute standard deviation across multiple variables.
CONSEC
: Compute consecutive identical digits across multiple variables (especially useful in detecting careless responding).
d=data.table(x1=1:5, x4=c(2,2,5,4,5), x3=c(3,2,NA,NA,5), x2=c(4,4,NA,2,5), x5=c(5,4,1,4,5)) d ## I deliberately set this order to show you ## the difference between "vars" and "varrange". d[,`:=`( na=COUNT(d, "x", 1:5, value=NA), n.2=COUNT(d, "x", 1:5, value=2), sum=SUM(d, "x", 1:5), m1=MEAN(d, "x", 1:5), m2=MEAN(d, vars=c("x1", "x4")), m3=MEAN(d, varrange="x1:x2", rev="x2", likert=1:5), cons1=CONSEC(d, "x", 1:5), cons2=CONSEC(d, varrange="x1:x5") )] d data=as.data.table(bfi) data[,`:=`( E=MEAN(d, "E", 1:5, rev=c(1,2), likert=1:6), O=MEAN(d, "O", 1:5, rev=c(2,5), likert=1:6) )] data
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