The strings are part of urls of which I stripped out the base.
parse detects four urls in some html file. I've narrowed down the problem to this:
REBOL []
images: [{,W,H,wi,1TV1Rvu8EF9FDdUxKy+hTKK/RNifw3WQDJEI/sYkX78tyNifGd0/U4RpaBox1rO448B4dv24sYoTgxOMVC7Lz5J9sJXlk0nkM89n55HzX7qbRiX/cSkd3lepAEIj3LVTN7gmQLCI2+INwwg18IyDklZ3VZWkw011+77dkfgTTRlRaY397ricx4dk4BTHvCLZ} {,W,H,wi,1TV1Rvu8EF9FDdUxKy+hTKK/RNifw3WQDJEI/sYkX78tyNifGd0/U4RpaBox1rO448B4dv24sYoTgxOMVC7Lz5J9sJXlk0nkM89n55HzX7qbRiX/cSkd3lepAEIj3LVTN7gmQLCI2+INwwg18IyDklZ3VZWkw011+77dkfgTTRlRaY397ricx4dk4BTHvCLZ} {,W,H,wi,1TV1Rvu8EF9FDdUxKy+hTKK/RNifw3WQDJEI/sYkX78wvYn3cKtEeN/9Y8EfNR8J48B4dv24sYoTgxOMVC7Lz5J9sJXlk0nkM89n55HzX7qbRiX/cSkd3lepAEIj3LVTN7gmQLCI2+INwwg18IyDklZ3VZWkw011+77dkfgTTRlRaY397ricx4dk4BTHvCLZ} {,W,H,wi,1TV1Rvu8EF9FDdUxKy+hTKK/RNifw3WQDJEI/sYkX78wvYn3cKtEeN/9Y8EfNR8J48B4dv24sYoTgxOMVC7Lz5J9sJXlk0nkM89n55HzX7qbRiX/cSkd3lepAEIj3LVTN7gmQLCI2+INwwg18IyDklZ3VZWkw011+77dkfgTTRlRaY397ricx4dk4BTHvCLZ}]
print join "before: " length? images
unique images
print join "after: " length? images
print join "1=2? " images/1 = images/2
print join "1=3? " images/1 = images/3
print join "1=4? " images/1 = images/4
print join "2=3? " images/2 = images/3
print join "2=4? " images/2 = images/4
print join "3=4? " images/3 = images/4
As can be seen, urls 1 and 2 are identical, and the same can be said to urls 3 and 4. Still, unique doesn't remove the duplicates. Why does this happen, how to deal with it?
UNIQUE does not modify original series. Whether function modifies is usually mentioned in it's help string, see SORT for example. Just set your block to the result of UNIQUE, like this:
>> a: [1 2 3 4 3 4 4]
== [1 2 3 4 3 4 4]
>> unique a
== [1 2 3 4]
>> a
== [1 2 3 4 3 4 4]
>> a: unique a
== [1 2 3 4]
>> a
== [1 2 3 4]