Basic operators for item pool objects

Source: R/item_pool_operators.R

Create a subset of an item_pool object:

  • pool[i]

  • subsetItemPool(pool, i)

Combine two item_pool objects:

  • c(pool1, pool2)

  • combineItemPool(pool1, pool2)

  • pool1 + pool2

pool1 - pool2 excludes items in pool2 from pool1.

pool1 == pool2 tests whether two item_pool objects are identical.

subsetItemPool(x, i = NULL)

combineItemPool(x1, x2, unique = TRUE, verbose = TRUE)

# S4 method for item_pool,numeric
[(x, i, j, ..., drop = TRUE)

# S4 method for item_pool
c(x, ...)

# S3 method for item_pool
+(x1, x2)

# S3 method for item_pool
-(x1, x2)

# S3 method for item_pool
==(x1, x2)

Arguments

x, x1, x2

an item_pool object.

i

item indices to use in subsetting.

unique

if TRUE, remove items with duplicate IDs after combining. (default = TRUE)

verbose

if TRUE, raise a warning if duplicate IDs are found after combining. (default = TRUE)

j, drop, ...

not used, exists for compatibility.

Examples

p1 <- itempool_science[1:100]
p2 <- c(itempool_science, itempool_reading)
p3 <- p2 - p1

p1 <- itempool_science[1:500]
p2 <- itempool_science - p1
p3 <- itempool_science[501:1000]
identical(p2, p3)  ## TRUE
#> [1] TRUE

p <- p1 + p3
p == itempool_science ## TRUE
#> [1] FALSE