utils: Move unique_everseen helper to utils

Author: ales-erjavec

Orange/widgets/data/owcsvimport.py

@@ -26,7 +26,7 @@
 
 import typing
 from typing import (
-    List, Tuple, Dict, Optional, Any, Callable, Iterable, Hashable,
+    List, Tuple, Dict, Optional, Any, Callable, Iterable,
     Union, AnyStr, BinaryIO, Set
 )
 
@@ -51,7 +51,9 @@
 
 from Orange.widgets import widget, gui, settings
 from Orange.widgets.utils.concurrent import PyOwned
-from Orange.widgets.utils import textimport, concurrent as qconcurrent
+from Orange.widgets.utils import (
+    textimport, concurrent as qconcurrent, unique_everseen
+)
 from Orange.widgets.utils.overlay import OverlayWidget
 from Orange.widgets.utils.settings import (
     QSettings_readArray, QSettings_writeArray
@@ -1033,7 +1035,7 @@ def _restoreState(self):
                 sitems.append(item_)
 
         items = sitems + items
-        items = unique(items, key=lambda t: pathnormalize(t[0]))
+        items = unique_everseen(items, key=lambda t: pathnormalize(t[0]))
 
         curr = self.recent_combo.currentIndex()
         if curr != -1:
@@ -1491,32 +1493,6 @@ def index_where(iterable, pred):
     return None
 
 
-def unique(iterable, key=None):
-    # type: (Iterable[T], Optional[Callable[[T], Hashable]]) -> Iterable[T]
-    """
-    Return an iterator over unique elements of `iterable`.
-
-    If `key` is supplied it is used as a substitute for determining
-    'uniqueness' of elements.
-
-    Parameters
-    ----------
-    iterable : Iterable[T]
-    key : Callable[[T], Hashable]
-
-    Returns
-    -------
-    unique : Iterable[T]
-    """
-    seen = set()
-    if key is None:
-        key = lambda t: t
-    for el in iterable:
-        el_k = key(el)
-        if el_k not in seen:
-            seen.add(el_k)
-            yield el
-
 
 def samepath(p1, p2):
     # type: (str, str) -> bool

Orange/widgets/utils/__init__.py

@@ -1,7 +1,7 @@
 import inspect
 import sys
 from collections import deque
-from typing import TypeVar, Deque, Callable, Any, Iterable
+from typing import TypeVar, Callable, Any, Iterable, Optional, Hashable
 
 from AnyQt.QtCore import QObject
 
@@ -81,7 +81,6 @@ def mypredicate(x):
     return inspect.getmembers(obj, mypredicate)
 
 
-
 _T1 = TypeVar("_T1")
 
 
@@ -90,3 +89,30 @@ def apply_all(seq, op):
     """Apply `op` on all elements of `seq`."""
     # from itertools recipes `consume`
     deque(map(op, seq), maxlen=0)
+
+
+def unique_everseen(iterable, key=None):
+    # type: (Iterable[_T1], Optional[Callable[[_T1], Hashable]]) -> Iterable[_T1]
+    """
+    Return an iterator over unique elements of `iterable` preserving order.
+
+    If `key` is supplied it is used as a substitute for determining
+    'uniqueness' of elements.
+
+    Parameters
+    ----------
+    iterable : Iterable[T]
+    key : Callable[[T], Hashable]
+
+    Returns
+    -------
+    unique : Iterable[T]
+    """
+    seen = set()
+    if key is None:
+        key = lambda t: t
+    for el in iterable:
+        el_k = key(el)
+        if el_k not in seen:
+            seen.add(el_k)
+            yield el