把scala list的幾種常見方法梳理彙總如下，日常開發場景基本上夠用了。
建立列表
scala
>
val days
=list
("sunday"
,"monday"
,"tuesday"
,"wednesday"
,"thursday"
,"friday"
,"saturday"
)days
:list
[string]=
list
(sunday
,monday
,tuesday
,wednesday
,thursday
,friday
,saturday
)
scala
>
val l
=nill:
scala
.collection
.immutable
.nil
.type
=list
()scala
>
val l
=list()l
:list
[nothing]=
list
()
scala
>
val l
="hello"
::"hi"
::"hah"
::"wow"
::"woow"
::nill:
list
[string]=
list
(hello,hi
,hah
,wow
,woow
)
scala
>
val wow =l
:::list
("wooow"
,"woooow"
)wow
:list
[string]=
list
(hello,hi
,hah
,wow
,woow
,wooow
,woooow
)
scala
>l(
3)res0
:string
=wow
scala
>l.
count(s
=>s.
length ==3
)res1
:int
=2
scala
>l.
drop(2
)res2
:list
[string]=
list
(hah
,wow
,woow
)scala
>
lres3
:list
[string]=
list
(hello,hi
,hah
,wow
,woow
)
scala
>l.
dropright(2
)res5
:list
[string]=
list
(hello,hi
,hah
)scala
>
lres6
:list
[string]=
list
(hello,hi
,hah
,wow
,woow
)
scala
>l.
exists(s
=>
s ==
"hah"
)res7
:boolean
=true
scala
>l.
filter(s
=>s.
length ==3
)res8
:list
[string]=
list
(hah
,wow
)
scala
>l.
forall(s
=>s.
startswith
("h"
))res10
:boolean
=false
scala
>l.
forall(s
=>s.
endswith
("w"
))res11
:boolean
=false
scala
>l.
foreach(s
=>
print(s
+' '
))hello
hihah
wow woow
scala
>l.
head
res17
:string
=hello
scala
>l.
last
res20
:string
=woow
scala
>l.
init
res18
:list
[string]=
list
(hello,hi
,hah
,wow
)
scala
>l.
tail
res49
:list
[string]=
list(hi
,hah
,wow
,woow
)
scala
>l.
isempty
res19
:boolean
=false
scala
>l.
length
res21
:int
=5
scala
>l.
map(
s =>
)res29
:list
[string]=
list(10
-olleh,10
-ih,10
-hah,10
-wow,10
-woow
)
scala
>l.
mkstring
(", "
)res30
:string
=hello,hi
,hah
,wow
,woow
scala
>l.
reverse
res41
:list
[string]=
list
(woow
,wow
,hah,hi
,hello
)
scala
>l.
sortwith(_
.compareto(_
)<0)
res48
:list
[string]=
list
(hah
,hello,hi
,woow
,wow
)
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