String in ArrayList <Long>
I currently have:
String a = "123.5950,555,5973.1,6321.905,6411.810000000001,6591.855"
I can turn it into a list of arrays of strings and then into a list of Longs arrays:
ArrayList<String> vals = new ArrayList<String>(Arrays.asList(a.split(","));
ArrayList<Long> longs = new ArrayList<>();
for(String ks : vals){
longs.add(Long.parseLong(ks));
}
I tried to do it with help Stream
to make it more "fun", but it seems to fail with this:
ArrayList<Long> longs = a.stream().map(Long::parseLong).collect(Collectors.toList());
I don't think the for loop is very nifty, how can I do it with Stream
?
Edit: copied to original line incorrectly
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You need to create a stream from the result String.split
:
final List<Long> longs = Arrays
.stream(a.split(","))
.map(Long::parseLong)
.collect(Collectors.toList());
Also, it Collectors.toList()
will return an interface List
, not a specific implementation ArrayList
.
If you really want a list of arrays, you need to copy it:
new ArrayList<>(longs);
Edit:
As @shmosel pointed out, you can directly collect a list of arrays withCollectors.toCollection(ArrayList::new)
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You cannot pass String
without dividing it. Two ways to split into a stream:
Arrays.stream(a.split(","))
or
Pattern.compile(",").splitAsStream(a)
It also collect(Collectors.toList())
returns List
instead of ArrayList
. And I'm not sure why you expect it parseLong()
to work with these lines.
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String a = "123.5950.555,5973.1,6321.905,6411.810000000001,6591.855";
List<Double> doubleList = Arrays.stream(a.split(","))
.map(Doubles::tryParse)
.collect(Collectors.toList());
System.out.println(doubleList);
Note: used here Doubles#tryParse
from Guava.
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