Re: How to check variables for uniqueness ?
John Ersatznom wrote:
Andrew Thompson wrote:
Patricia Shanahan wrote:
Andrew Thompson wrote:
krisl...@gmail.com wrote:
...
I have eight variables : var1, var2... var 8. All types String.
How to check that each variables has unique values ?
One way would be to create a Map, iterate the
var's and if not present in the map, add the value
as a key, else return false.
...
Any particular reason for Map, rather than Set?
You mean besides, 'lack of enough consultation
of the relevant docs.'? ;-)
Note that the result of a Set add call is true if, and only if, the
value is not already in the Set.
A Set sounds the go - it is just right for this task.
HashSet<String> foo = new HashSet<String>();
foo.add(var1);
foo.add(var2);
foo.add(var3);
foo.add(var4);
foo.add(var5);
foo.add(var6);
foo.add(var7);
foo.add(var8);
if (foo.size() < 8)
duplicateExists();
else
duplicateDoesNotExist();
If you actually need to identify the specific duplicate pairs, you need
to compare them one by one -- 1 with all the others, 2 with all the
higher-numbered ones, and so on up to 7 and 8, using equals().
To save repititious writing, I'm going to assume the strings are in an
array. The equivalent of your code would be:
HashSet<String> foo = new HashSet<String>();
for(String v:vars){
foo.add(v);
}
if (foo.size() < vars.length)
duplicateExists();
else
duplicateDoesNotExist();
You can simplify finding specific duplicates by checking the foo.add
results:
HashSet<String> foo = new HashSet<String>();
for(int i=0; i<vars.length; i++){
if(!foo.add(vars[i]){
for(int j=0; j<i; j++){
if(vars[i].equals(vars[j])){
reportDuplicate(i,j);
}
}
}
}
A true result from foo.add means the string was actually added to the
set, so it has no duplicate with a lower index.
Patricia
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