Java8 understand stream filter 2020-07-29 08:56
I knew a long time ago that there is a method filter in stream. Every time I use it, I don’t know how it filters internally. Will he remove the qualified ones or leave the qualified ones? Every time I need to run the code to make sure my logic is correct.
I understand method filter like this.
If you do not use stream to achieve filtering, the approximate code should look like the following
for(Item item:itemCollection){
if(item meets the conditions){
do something here
}
}
The question is what needs to be done after meeting the conditions. This element must not be removed from the collection. That would cause loop errors. So the code should generally look like this.
Collection c = new Collection()
for(Item item:itemCollection){
if(item meets the conditions){
c.add(item)
}
}
At this point, the logic is very clear. The logic in method filter must be that the elements that meet this condition are left instead of being removed.
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