I attached a patch for unique (with a test case) based on Norbert's suggestion. I removed the sort keyword since iterable arrays would be sorted anyway. The function uses a python set, and I was wondering if it is ok to assume that everyone running numpy has a python version >= 2.3 ?
David
Index: numpy/lib/tests/test_function_base.py
===================================================================
--- numpy/lib/tests/test_function_base.py (revision 2791)
+++ numpy/lib/tests/test_function_base.py (working copy)
@@ -353,8 +353,19 @@
(a,b)=histogram(linspace(0,10,100))
assert(all(a==10))
+class test_unique(NumpyTestCase):
+ def check_simple(self):
+ x = array([4,3,2,1,1,2,3,4, 0])
+ assert(all(unique(x) == [0,1,2,3,4]))
+ assert(unique(array([1,1,1,1,1])) == array([1]))
+ # from ??? import inf
+ #x = array([-0.5, -4.2, 0., inf, -5, -4.2, 0, -1/2., inf])
+ #assert(all(unique(x) == [-5, -4.2, -0.5, 0, inf]))
+ x = ['widget', 'ham', 'foo', 'bar', 'foo', 'ham']
+ assert(all(unique(x) == ['bar', 'foo', 'ham', 'widget']))
+ x = array([5+6j, 1+1j, 1+10j, 10, 5+6j])
+ assert(all(unique(x) == [1+1j, 1+10j, 5+6j, 10]))
-
def compare_results(res,desired):
for i in range(len(desired)):
assert_array_equal(res[i],desired[i])
Index: numpy/lib/function_base.py
===================================================================
--- numpy/lib/function_base.py (revision 2791)
+++ numpy/lib/function_base.py (working copy)
@@ -474,17 +474,23 @@
else: last = last - 1
return filt[first:last]
-def unique(inseq):
- """Return unique items (in sorted order) from a 1-dimensional sequence.
+def unique(x):
+ """Return sorted unique items from a one dimensional sequence.
+
+ Example:
+ >>> unique([5,2,4,0,4,4,2,2,1])
+ array([0,1,2,4,5])
"""
- # Dictionary setting is quite fast.
- set = {}
- for item in inseq:
- set[item] = None
- val = asarray(set.keys())
- val.sort()
- return val
-
+ try:
+ tmp = x.flatten()
+ tmp.sort()
+ idx = concatenate(([True],tmp[1:]!=tmp[:-1]))
+ return tmp[idx]
+ except AttributeError:
+ items = list(set(x))
+ items.sort()
+ return asarray(items)
+
def extract(condition, arr):
"""Return the elements of ravel(arr) where ravel(condition) is True
(in 1D).
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