QList
Bases: list
QList
is a python list extension that adds several chainable, lazy
evaluated methods to the standard list
.
Found in qwlist.QList
Source code in src\qwlist\qwlist.py
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cycle()
Returns a Lazy[T]
that cycles through the elements of the QList
that means
on achieving the last element the iteration starts from the beginning. The
returned Lazy
object has no end (infinite iterator) unless the QList
is empty
in which case cycle returns an empty Lazy
object (empty iterator).
Returns: Lazy[T]
Examples:
>>> QList([1, 2, 3]).cycle().take(7).collect()
[1, 2, 3, 1, 2, 3, 1]
Source code in src\qwlist\qwlist.py
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eager()
Changes QList
into EagerQList
.
Returns: EagerQList[T]
Source code in src\qwlist\qwlist.py
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enumerate(start=0)
Returns a Lazy
object with index-value pairs as its elements. Index starts at
the given position start
(defaults to 0).
Returns: Lazy[tuple[int, T]]
Examples:
>>> QList(['a', 'b', 'c']).enumerate().collect()
[(0, 'a'), (1, 'b'), (2, 'c')]
Source code in src\qwlist\qwlist.py
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filter(pred)
Returns a Lazy
object containing all values from the QList
for which
the predicate holds true.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
pred |
Callable[[T], bool]
|
|
required |
Returns: Lazy[T]
Examples:
>>> QList([1, 2, 3, 4]).filter(lambda x: x < 3).collect()
[1, 2]
Source code in src\qwlist\qwlist.py
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flatmap(mapper)
Applies the mapper function to each element of the QList
and flattens the results.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
mapper |
Callable[[T], Iterable[K]]
|
|
required |
Returns: Lazy[K]
Examples:
>>> QList([1, 2]).flatmap(lambda x: [x, x]).qlist()
[1, 1, 2, 2]
Source code in src\qwlist\qwlist.py
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flatten()
If self is a QList of Iterable[T] flatten concatenates all iterables into a single list and returns a Lazy[T] object Returns: Lazy[T]
Source code in src\qwlist\qwlist.py
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fold(operation, init)
Given the combination operator reduces the QList
by processing
its values, building up the final value.
Other names: fold_left, reduce, accumulate, aggregate
Parameters:
Name | Type | Description | Default |
---|---|---|---|
operation |
Callable[[K, T], K]
|
|
required |
init |
K
|
initial value for the combination operator. |
required |
Returns: K
Examples:
>>> QList([1, 2, 3]).fold(lambda acc, x: acc + x, 0)
6
Source code in src\qwlist\qwlist.py
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fold_right(operation, init)
Given the combination operator reduces the QList
by processing
its values, building up the final value.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
operation |
Callable[[K, T], K]
|
|
required |
init |
K
|
initial value for the combination operator. |
required |
Returns: K
Examples:
>>> QList([1, 2, 3]).fold_right(lambda acc, x: acc + x, 0)
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Source code in src\qwlist\qwlist.py
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foreach(action)
Applies the given function to each of the QList
elements.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
action |
Callable[[T], None]
|
|
required |
Returns: None
Source code in src\qwlist\qwlist.py
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len()
Returns the len of the QList
(time complexity: O(1)
)
Returns: int
Source code in src\qwlist\qwlist.py
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list()
Changes QList
into list
.
Returns: list[T]
Source code in src\qwlist\qwlist.py
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map(mapper)
Returns a Lazy
object containing all values from QList
with
the mapping function applied on them.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
mapper |
Callable[[T], K]
|
|
required |
Returns: Lazy[K]
Source code in src\qwlist\qwlist.py
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skip(n)
Skips n first elements of the QList.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
n |
int
|
numbers of elements to skip. Should be non-negative |
required |
Returns: Lazy[T]
Examples:
>>> QList(range(10)).skip(2).collect()
[2, 3, 4, 5, 6, 7, 8, 9]
Source code in src\qwlist\qwlist.py
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slice(s)
Calling this method with s
equal to slice(3)
works similarly to
list[:3]
but is lazy evaluated.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
s |
slice
|
slice object |
required |
Returns: Lazy[T]
Source code in src\qwlist\qwlist.py
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sorted(key=None, reverse=False)
Returns a new QList
containing all items from the original list in ascending order.
A custom key function can be supplied to customize the sort order, and the reverse flag can be set to request the result in descending order.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
Callable[[T], SupportsLessThan]
|
|
None
|
reverse |
bool
|
if set to |
False
|
Returns: QList[T]
Source code in src\qwlist\qwlist.py
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take(n)
Takes n first elements of the QList.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
n |
int
|
int - numbers of elements to take. Should be non-negative |
required |
Returns: Lazy[T]
Examples:
>>> QList(range(10)).take(2).collect()
[0, 1]
Source code in src\qwlist\qwlist.py
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zip(other)
Combines this QList
with the given Iterable
elementwise as tuples.
The returned Lazy
objects yields at most the number of elements of
the shorter sequence (self
or Iterable
).
Parameters:
Name | Type | Description | Default |
---|---|---|---|
other |
Iterable[K]
|
iterable to zip with this |
required |
Returns: Lazy[tuple[T, K]]
Examples:
>>> Lazy([1, 2, 3]).zip(['a', 'b', 'c']).collect()
[(1, 'a'), (2, 'b'), (3, 'c')]
Source code in src\qwlist\qwlist.py
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