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<div>Scala 2.1.5</div>
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class
List
[ a ]
extends
java.lang.Object with
scala.Seq[a] with
scala.ScalaObjecta
. This class comes with two implementing case
classes scala.Nil
and scala.::
that
implement the abstract members isEmpty
,
head
and tail
.Constructor Summary | |
def
this
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Def Summary | |
def
::
[ a <: b ]
( x : b )
: scala.List[b]
Add an element x at the beginning of this list.
Ex:1 :: [2, 3] = [2, 3].::(1) = [1, 2, 3] .
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def
:::
[ a <: b ]
( prefix : scala.List[b] )
: scala.List[b]
Returns a list resulting from the concatenation of the given list prefix and this list.
Ex:[1, 2] ::: [3, 4] = [3, 4].:::([1, 2]) = [1, 2, 3, 4] .
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def
apply
( n : scala.Int )
: a
Returns the n -th element of this list. The first element
(head of the list) is at position 0.
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def
break
( p : (a) => scala.Boolean )
: scala.Tuple2[scala.List[a],scala.List[a]]
Like span but with the predicate inverted.
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def
contains
( elem : scala.Any )
: scala.Boolean
Tests if the given value elem is a member of this
iterable object.
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def
count
( p : (a) => scala.Boolean )
: scala.Int
Count the number of elements in the list which satisfy a predicate. |
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def
diff
[ a <: b ]
( that : scala.List[b] )
: scala.List[b]
Computes the difference between this list and the given list that .
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override
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def
drop
( n : scala.Int )
: scala.List[a]
Returns the list without its n first elements.
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def
dropRight
( n : scala.Int )
: scala.List[a]
Returns the list wihout its rightmost n elements.
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def
dropWhile
( p : (a) => scala.Boolean )
: scala.List[a]
Returns the longest suffix of this list whose first element does not satisfy the predicate p .
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def
elements
: scala.Iterator[a]
Returns the elements in the list as an iterator |
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override
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def
exists
( p : (a) => scala.Boolean )
: scala.Boolean
Tests the existence in this list of an element that satisfies the predicate p .
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def
filter
( p : (a) => scala.Boolean )
: scala.List[a]
Returns all the elements of this list that satisfy the predicate p . The order of the elements is preserved.
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override
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def
find
( p : (a) => scala.Boolean )
: scala.Option[a]
Find and return the first element of the list satisfying a predicate, if any. |
def
flatMap
[ b ]
( f : (a) => scala.List[b] )
: scala.List[b]
Applies the given function f to each element of
this list, then concatenates the results.
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override
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def
foldLeft
[ b ]
( z : b ) ( f : (b, a) => b )
: b
Combines the elements of this list together using the binary operator op , from left to right, and starting with
the value z .
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override
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def
foldRight
[ b ]
( z : b ) ( f : (a, b) => b )
: b
Combines the elements of this list together using the binary operator op , from rigth to left, and starting with
the value z .
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override
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def
forall
( p : (a) => scala.Boolean )
: scala.Boolean
Tests if the predicate p is satisfied by all elements
in this list.
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override
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def
foreach
( f : (a) => scala.Unit )
: scala.Unit
Apply the given function f to each element of this list
(while respecting the order of the elements).
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def
head
: a
Returns this first element of the list. |
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def
indices
: scala.List[scala.Int]
Creates a list with all indices in the list. This is equivalent to a call to List.range(0, xs.length) .
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def
init
: scala.List[a]
Returns the list without its last element. |
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def
intersect
[ a <: b ]
( that : scala.List[b] )
: scala.List[b]
Computes the intersection between this list and the given list that .
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def
isEmpty
: scala.Boolean
Returns true if the list does not contain any elements. |
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def
last
: a
Returns the last element of this list. |
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def
length
: scala.Int
Returns the number of elements in the list. |
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def
map
[ b ]
( f : (a) => b )
: scala.List[b]
Returns the list resulting from applying the given function f to each
element of this list.
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def
partition
( p : (a) => scala.Boolean )
: scala.Tuple2[scala.List[a],scala.List[a]]
Partition the list in two sub-lists according to a predicate. |
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def
reduceLeft
[ a <: b ]
( f : (b, b) => b )
: b
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def
reduceRight
[ a <: b ]
( f : (b, b) => b )
: b
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def
remove
( p : (a) => scala.Boolean )
: scala.List[a]
Removes all elements of the list which satisfy the predicate p . This is like filter with the
predicate inversed.
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def
removeDuplicates
: scala.List[a]
Removes redundant elements from the list. Uses the method ==
to decide if two elements are identical.
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def
reverse
: scala.List[a]
Reverses the elements of this list. Ex: [1, 2, 3] reverse = [3, 2, 1] .
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def
reverseMap
[ b ]
( f : (a) => b )
: scala.List[b]
Apply a function to all the elements of the list, and return the reversed list of results. This is equivalent to a call to map
followed by a call to reverse , but more efficient.
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def
reverse_:::
[ a <: b ]
( prefix : scala.List[b] )
: scala.List[b]
Reverse the given prefix and append the current list to that. This function is equivalent to an application of reverse
on the prefix followed by a call to ::: , but more
efficient (and tail recursive).
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def
sort
( lt : (a, a) => scala.Boolean )
: scala.List[a]
Sort the list according to the comparison function <(e1: a, e2: a) => Boolean ,
which should be true iff e1 is smaller than e2.
Note: The current implementation is inefficent for
already sorted lists.
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def
span
( p : (a) => scala.Boolean )
: scala.Tuple2[scala.List[a],scala.List[a]]
Returns the longest prefix of the list whose elements all satisfy the given predicate, and the rest of the list. |
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def
splitAt
( n : scala.Int )
: scala.Tuple2[scala.List[a],scala.List[a]]
Split the list at a given point and return the two parts thus created. |
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override protected
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def
stringPrefix
: java.lang.String
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def
tail
: scala.List[a]
Returns this list without its first element. |
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override
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def
take
( n : scala.Int )
: scala.List[a]
Returns the n first elements of this list.
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def
takeRight
( n : scala.Int )
: scala.List[a]
Returns the rightmost n elements from this list.
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def
takeWhile
( p : (a) => scala.Boolean )
: scala.List[a]
Returns the longest prefix of this list whose elements satisfy the predicate p .
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override
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def
toList
: scala.List[a]
Overrides the method in Iterable for efficiency. |
def
union
[ a <: b ]
( that : scala.List[b] )
: scala.List[b]
Computes the union of this list and the given list that .
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def
zip
[ b ]
( that : scala.List[b] )
: scala.List[scala.Tuple2[a,b]]
Returns a list formed from this list and the specified list that by associating each element of the former with
the element at the same position in the latter.
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def
zipAll
[ b , a <: c , b <: d ]
( that : scala.List[b] , thisElem : c , thatElem : d )
: scala.List[scala.Tuple2[c,d]]
Returns a list formed from this list and the specified list that by associating each element of the former with
the element at the same position in the latter.
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def
zipWithIndex
: scala.List[scala.Tuple2[a,scala.Int]]
Return an list that pairs each element of this list with its index, counting from 0. |
Constructor Detail |
def
this
Def Detail |
def
::
[ a <: b ]( x : b ) : scala.List[b]
x
at the beginning of this list.
Ex:1 :: [2, 3] = [2, 3].::(1) = [1, 2, 3]
.x
appended at the beginning.def
:::
[ a <: b ]( prefix : scala.List[b] ) : scala.List[b]
prefix
and this list.
Ex:[1, 2] ::: [3, 4] = [3, 4].:::([1, 2]) = [1, 2, 3, 4]
.def
apply
( n : scala.Int ) : a
n
-th element of this list. The first element
(head of the list) is at position 0.n
in this list.java.lang.RuntimeException
if the list is too short.def
break
( p : (a) => scala.Boolean ) : scala.Tuple2[scala.List[a],scala.List[a]]
span
but with the predicate inverted.def
contains
( elem : scala.Any ) : scala.Boolean
elem
is a member of this
iterable object.==
) to elem
.def
count
( p : (a) => scala.Boolean ) : scala.Int
p
.def
diff
[ a <: b ]( that : scala.List[b] ) : scala.List[b]
that
.that
.def
drop
( n : scala.Int ) : scala.List[a]
n
first elements.n
first elements.def
dropRight
( n : scala.Int ) : scala.List[a]
n
elements.n
of the listjava.lang.RuntimeException
if the list is too short.def
dropWhile
( p : (a) => scala.Boolean ) : scala.List[a]
p
.p
.def
elements
: scala.Iterator[a]
def
exists
( p : (a) => scala.Boolean ) : scala.Boolean
p
.p
.def
filter
( p : (a) => scala.Boolean ) : scala.List[a]
p
. The order of the elements is preserved.p
.def
find
( p : (a) => scala.Boolean ) : scala.Option[a]
p
,
or None
if none exists.def
flatMap
[ b ]( f : (a) => scala.List[b] ) : scala.List[b]
f
to each element of
this list, then concatenates the results.f(a0) ::: ... ::: f(an)
if this list is
[a0, ..., an]
.def
foldLeft
[ b ]( z : b ) ( f : (b, a) => b ) : b
op
, from left to right, and starting with
the value z
.op(... (op(op(z,a0),a1) ...), an)
if the list
is [a0, a1, ..., an]
.def
foldRight
[ b ]( z : b ) ( f : (a, b) => b ) : b
op
, from rigth to left, and starting with
the value z
.a0 op (... op (an op z)...)
if the list
is [a0, a1, ..., an]
.def
forall
( p : (a) => scala.Boolean ) : scala.Boolean
p
is satisfied by all elements
in this list.p
.def
foreach
( f : (a) => scala.Unit ) : scala.Unit
f
to each element of this list
(while respecting the order of the elements).def
head
: a
java.lang.RuntimeException
if the list is empty.def
indices
: scala.List[scala.Int]
List.range(0, xs.length)
.def
init
: scala.List[a]
java.lang.RuntimeException
if the list is empty.def
intersect
[ a <: b ]( that : scala.List[b] ) : scala.List[b]
that
.that
.def
isEmpty
: scala.Boolean
def
last
: a
java.lang.RuntimeException
if the list is empty.def
length
: scala.Int
def
map
[ b ]( f : (a) => b ) : scala.List[b]
f
to each
element of this list.[f(a0), ..., f(an)]
if this list is [a0, ..., an]
.def
partition
( p : (a) => scala.Boolean ) : scala.Tuple2[scala.List[a],scala.List[a]]
p
and the list of all elements which do not. The
relative order of the elements in the sub-lists is the same as in
the original list.def
reduceLeft
[ a <: b ]( f : (b, b) => b ) : b
def
reduceRight
[ a <: b ]( f : (b, b) => b ) : b
def
remove
( p : (a) => scala.Boolean ) : scala.List[a]
p
. This is like filter
with the
predicate inversed.p
def
removeDuplicates
: scala.List[a]
==
to decide if two elements are identical.def
reverse
: scala.List[a]
[1, 2, 3] reverse = [3, 2, 1]
.def
reverseMap
[ b ]( f : (a) => b ) : scala.List[b]
map
followed by a call to reverse
, but more efficient.def
reverse_:::
[ a <: b ]( prefix : scala.List[b] ) : scala.List[b]
reverse
on the prefix followed by a call to :::
, but more
efficient (and tail recursive).def
sort
( lt : (a, a) => scala.Boolean ) : scala.List[a]
<(e1: a, e2: a) => Boolean
,
which should be true iff e1 is smaller than e2.
Note: The current implementation is inefficent for
already sorted lists.<(e1: a, e2: a) => Boolean
.def
span
( p : (a) => scala.Boolean ) : scala.Tuple2[scala.List[a],scala.List[a]]
p
, and the rest of the list.def
splitAt
( n : scala.Int ) : scala.Tuple2[scala.List[a],scala.List[a]]
n
elements, and the other elements.def
stringPrefix
: java.lang.String
def
tail
: scala.List[a]
java.lang.RuntimeException
if the list is empty.def
take
( n : scala.Int ) : scala.List[a]
n
first elements of this list.n
first elements of this list.def
takeRight
( n : scala.Int ) : scala.List[a]
n
elements from this list.n
of the listjava.lang.RuntimeException
if the list is too short.def
takeWhile
( p : (a) => scala.Boolean ) : scala.List[a]
p
.p
.def
toList
: scala.List[a]
def
union
[ a <: b ]( that : scala.List[b] ) : scala.List[b]
that
.that
.def
zip
[ b ]( that : scala.List[b] ) : scala.List[scala.Tuple2[a,b]]
that
by associating each element of the former with
the element at the same position in the latter.that
must have the same length as the self list.[(a0,b0), ..., (an,bn)]
when
[a0, ..., an] zip [b0, ..., bn]
is invoked.def
zipAll
[ b , a <: c , b <: d ]( that : scala.List[b] , thisElem : c , thatElem : d ) : scala.List[scala.Tuple2[c,d]]
that
by associating each element of the former with
the element at the same position in the latter.that
may have a different length as the self list.thisElem
is used to fill up the resulting list if
the self list is shorter than that
thatElem
is used to fill up the resulting list if
that
is shorter than the self list[(a0,b0), ..., (an,bn), (elem,bn+1), ..., (elem,bm)]
when [a0, ..., an] zip [b0, ..., bm]
is invoked where
m > n
.def
zipWithIndex
: scala.List[scala.Tuple2[a,scala.Int]]
start
the index of the first element(a0,0), (a0,1)...
where ai
are the elements from this iterator.