ifilter: Create a filtering iterator

In itertools: Iterator Tools

Description

The ifilter and ifilterfalse functions create iterators that return a subset of the values of the specified iterable. ifilter returns the values for which the pred function returns TRUE, and ifilterfalse returns the values for which the pred function returns FALSE.

Usage

ifilter(pred, iterable)
ifilterfalse(pred, iterable)

Arguments

pred	A function that takes one argument and returns TRUE or FALSE.
iterable	The iterable to iterate over.

Examples

# Return the odd numbers between 1 and 10
as.list(ifilter(function(x) x %% 2 == 1, icount(10)))

# Return the even numbers between 1 and 10
as.list(ifilterfalse(function(x) x %% 2 == 1, icount(10)))

Example output

Loading required package: iterators
[[1]]
[1] 1

[[2]]
[1] 3

[[3]]
[1] 5

[[4]]
[1] 7

[[5]]
[1] 9

[[1]]
[1] 2

[[2]]
[1] 4

[[3]]
[1] 6

[[4]]
[1] 8

[[5]]
[1] 10

itertools documentation built on May 2, 2019, 2:26 p.m.