RE: Find duplicates in a list

[Jay Lawrence]

I'm sure one of the cool macro libraries has an elegant solution already,
but here's one I just cooked up

------------ cut here ------------------

# Given a list with duplicates
ORIGINAL := A C B C B D A

# Build a new list in order with no dups
$(foreach V,$(ORIGINAL),$(if $(filter $V,$(NEW)),,$(eval NEW := $(NEW) $V)))

# Or just call sort, but the order may be different
SORTED = $(sort $(ORIGINAL))

result:
        @echo ORIGINAL = $(ORIGINAL)
        @echo NEW = $(NEW)
        @echo SORTED = $(SORTED)

------------------------------

Jay

-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of Sam Ravnborg
Sent: Sunday, July 27, 2014 5:59 AM
To: address@hidden
Subject: Find duplicates in a list

Hi all.

I'm trying to find a way to detect duplicate items in a list without
escaping to a shell.

Consider the following:

list := A B C A D C

In the list above A and C is duplicated.
I would like to find a way so I can find which items are duplicated and
print them out.

The solution should preferably work with gmake 3.81 and even better in make
3.80

Thanks in advance,

        Sam


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