集合常見的幾種遍歷方式

建立dog類用於存入集合遍歷

public

class
dogpublic string getname()
public
void
setname
(string name)
public
intgetage()
public
void
setage
(int age)
//重寫tostring方法
@override
public string tostring()
}

list

list=
newarraylist
();   			list.
add(
newdog
("小胡",8
));   			list.
add(
newdog
("小花",2
));   			list.
add(
newdog
("小花",2
));   			iterator
iterlist=list.
iterator()
;while
(iterlist.
hasnext()
)

for

(dog dog:list)

for

(int i=
0;isize()
;i++)~
~~**set集合泛型迭代*
*		set
set =
newhashset
();		set.
add(
newdog
("小胡",8
));		set.
add(
newdog
("小花",2
));		set.
add(
newdog
("小美",8
));		iterator
iterset=set.
iterator()
;while
(iterset.
hasnext()
)

for

(dog dogfor:set)

map

map=
newhashmap
();			map.
put(1,
newdog
("小胡",8
));			map.
put(2,
newdog
("小花",2
));			map.
put(2,
newdog
("小小",8
));			map.
put(2,
newdog
("小花",2
));

iterator

> itr=map.
entryset()
.iterator()
;while
(itr.
hasnext()
)

iterator

itr3=map.
keyset()
.iterator()
;while
(itr3.
hasnext()
)

iterator

itr4=map.
values()
.iterator()
;while
(itr4.
hasnext()
)

for

(map.entry
entry:map.
entryset()
)

集合的幾種遍歷方式

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遍歷集合的幾種方式

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幾種集合遍歷方式的效率對比

double time0 system currenttimemillis treeset.foreach o system out println o double time1 system currenttimemillis for person o treeset double time2 s...