Iter
Abstract type for iterators. Values that implement the iteration protocol
are instances of Iter, which can be used for type testing.
Iter is not constructible directly. See
Classes for defining custom iterators.
Inherits
Methods
next :default? :else?
Returns the next value from the iterator.
Parameters
| Name | Type | Description |
|---|---|---|
default |
value to return if the iterator is empty | |
else |
callable to invoke if the iterator is empty |
Errors
Raises IterStop when exhausted and no fallback
is provided.
all pred?
Returns true if every yielded value is truthy.
When pred is provided, it tests pred(value) instead.
Empty iterators return true.
any pred?
Returns true if any yielded value is truthy.
When pred is provided, it tests pred(value) instead.
Empty iterators return false.
count
Consumes the iterator and returns the number of yielded values.
fold init func
Consumes the iterator left-to-right, repeatedly applying func(acc, value).
Returns init unchanged if the iterator is empty.
chain ...values
Returns an iterator that yields this iterator followed by each additional iterable in sequence.
zip ...values
Returns an iterator that yields one tuple for each step across this iterator and the additional iterables. The zipped iterator stops as soon as any input is exhausted.
take n
Returns an iterator that yields at most n values.
Parameters
| Name | Type | Description |
|---|---|---|
n |
int | maximum values to yield |
Errors
Raises TypeError if n is not an Int.
Raises ValueError if n is negative.
skip n
Returns an iterator that discards the first n values, then yields the rest.
Parameters
| Name | Type | Description |
|---|---|---|
n |
int | values to discard |
Errors
Raises TypeError if n is not an Int.
Raises ValueError if n is negative.
enumerate
Returns an iterator that yields [index, value] tuples.
The first index is 0.
kv
Returns an iterator wrapper that preserves normal iteration, but opts into key/value spreading.
When spread in a keyed context such as a dict literal or argument spread, each yielded item must unpack into exactly two values.
let entries = ["x=1", "y=2"].iter().map do |e| e.split "="
assert_eq {...entries.kv()} {"x": "1", "y": "2"}
map func
Creates a wrapper Iter which yields func(value) for each value yielded by
the wrapper iterator.
filter pred
Creates a wrapper Iter which yields each value from the wrapper iterator
only if pred(value) is truthy.
find pred :default? :else?
Consumes the iterator and returns the first value where pred(value) is truthy.
Parameters
| Name | Type | Description |
|---|---|---|
pred |
callable used to test values | |
default |
value to return if no value matches | |
else |
callable to invoke if no value matches |
Errors
Raises RuntimeError if no value matches and
no fallback is provided.
min :default?
Consumes the iterator and returns the minimum yielded value.
Errors
Raises IterStop if the iterator is empty and no
default: is provided.
max :default?
Consumes the iterator and returns the maximum yielded value.
Errors
Raises IterStop if the iterator is empty and no
default: is provided.