diff options
Diffstat (limited to 'lib/spack/llnl/util/lang.py')
| -rw-r--r-- | lib/spack/llnl/util/lang.py | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/spack/llnl/util/lang.py b/lib/spack/llnl/util/lang.py index e474924507..69e0c886fb 100644 --- a/lib/spack/llnl/util/lang.py +++ b/lib/spack/llnl/util/lang.py @@ -589,20 +589,31 @@ def match_predicate(*args): return match -def dedupe(sequence): - """Yields a stable de-duplication of an hashable sequence +def dedupe(sequence, key=None): + """Yields a stable de-duplication of an hashable sequence by key Args: sequence: hashable sequence to be de-duplicated + key: callable applied on values before uniqueness test; identity + by default. Returns: stable de-duplication of the sequence + + Examples: + + Dedupe a list of integers: + + [x for x in dedupe([1, 2, 1, 3, 2])] == [1, 2, 3] + + [x for x in llnl.util.lang.dedupe([1,-2,1,3,2], key=abs)] == [1, -2, 3] """ seen = set() for x in sequence: - if x not in seen: + x_key = x if key is None else key(x) + if x_key not in seen: yield x - seen.add(x) + seen.add(x_key) def pretty_date(time, now=None): |