add bisect

python/bisect.py

@@ -0,0 +1,72 @@
+"""Bisection algorithms."""
+
+def insort_right(a, x, lo=0, hi=None):
+    """Insert item x in list a, and keep it sorted assuming a is sorted.
+
+    If x is already in a, insert it to the right of the rightmost x.
+
+    Optional args lo (default 0) and hi (default len(a)) bound the
+    slice of a to be searched.
+    """
+
+    lo = bisect_right(a, x, lo, hi)
+    a.insert(lo, x)
+
+def bisect_right(a, x, lo=0, hi=None):
+    """Return the index where to insert item x in list a, assuming a is sorted.
+
+    The return value i is such that all e in a[:i] have e <= x, and all e in
+    a[i:] have e > x.  So if x already appears in the list, a.insert(x) will
+    insert just after the rightmost x already there.
+
+    Optional args lo (default 0) and hi (default len(a)) bound the
+    slice of a to be searched.
+    """
+
+    if lo < 0:
+        raise ValueError('lo must be non-negative')
+    if hi is None:
+        hi = len(a)
+    while lo < hi:
+        mid = (lo+hi)//2
+        if x < a[mid]: hi = mid
+        else: lo = mid+1
+    return lo
+
+def insort_left(a, x, lo=0, hi=None):
+    """Insert item x in list a, and keep it sorted assuming a is sorted.
+
+    If x is already in a, insert it to the left of the leftmost x.
+
+    Optional args lo (default 0) and hi (default len(a)) bound the
+    slice of a to be searched.
+    """
+
+    lo = bisect_left(a, x, lo, hi)
+    a.insert(lo, x)
+
+
+def bisect_left(a, x, lo=0, hi=None):
+    """Return the index where to insert item x in list a, assuming a is sorted.
+
+    The return value i is such that all e in a[:i] have e < x, and all e in
+    a[i:] have e >= x.  So if x already appears in the list, a.insert(x) will
+    insert just before the leftmost x already there.
+
+    Optional args lo (default 0) and hi (default len(a)) bound the
+    slice of a to be searched.
+    """
+
+    if lo < 0:
+        raise ValueError('lo must be non-negative')
+    if hi is None:
+        hi = len(a)
+    while lo < hi:
+        mid = (lo+hi)//2
+        if a[mid] < x: lo = mid+1
+        else: hi = mid
+    return lo
+
+# Create aliases
+bisect = bisect_right
+insort = insort_right

src/pocketpy.h

@@ -732,6 +732,7 @@ void VM::post_init(){
     _lazy_modules["functools"] = kPythonLibs["functools"];
     _lazy_modules["collections"] = kPythonLibs["collections"];
     _lazy_modules["heapq"] = kPythonLibs["heapq"];
+    _lazy_modules["bisect"] = kPythonLibs["bisect"];
 
     CodeObject_ code = compile(kPythonLibs["builtins"], "<builtins>", EXEC_MODE);
     this->_exec(code, this->builtins);

tests/70_bisect.py

@@ -0,0 +1,44 @@
+from bisect import bisect_left, bisect_right, insort_left, insort_right
+
+a = [1, 1, 2, 6, 7, 8, 16, 22]
+
+assert bisect_left(a, 23) == 8  # 23 does not exist in the list
+assert bisect_left(a, 22) == 7  # 22 exists in the list
+assert bisect_left(a, 0) == 0   # 0 does not exist in the list
+assert bisect_left(a, 1) == 0   # 1 exists in the list
+assert bisect_left(a, 5) == 3   # 5 does not exist in the list
+assert bisect_left(a, 6) == 3   # 6 does exist in the list
+
+# test bisect_right
+assert bisect_right(a, 23) == 8  # 23 does not exist in the list
+assert bisect_right(a, 22) == 8  # 22 exists in the list
+assert bisect_right(a, 0) == 0   # 0 does not exist in the list
+assert bisect_right(a, 1) == 2   # 1 exists in the list
+assert bisect_right(a, 5) == 3   # 5 does not exist in the list
+assert bisect_right(a, 6) == 4   # 6 does exist in the list
+
+# test insort_left
+insort_left(a, 23)
+assert a == [1, 1, 2, 6, 7, 8, 16, 22, 23]
+
+insort_left(a, 0)
+assert a == [0, 1, 1, 2, 6, 7, 8, 16, 22, 23]
+
+insort_left(a, 5)
+assert a == [0, 1, 1, 2, 5, 6, 7, 8, 16, 22, 23]
+
+insort_left(a, 1)
+assert a == [0, 1, 1, 1, 2, 5, 6, 7, 8, 16, 22, 23]
+
+# test insort_right
+insort_right(a, 23)
+assert a == [0, 1, 1, 1, 2, 5, 6, 7, 8, 16, 22, 23, 23]
+
+insort_right(a, 0)
+assert a == [0, 0, 1, 1, 1, 2, 5, 6, 7, 8, 16, 22, 23, 23]
+
+insort_right(a, 5)
+assert a == [0, 0, 1, 1, 1, 2, 5, 5, 6, 7, 8, 16, 22, 23, 23]
+
+insort_right(a, 1)
+assert a == [0, 0, 1, 1, 1, 1, 2, 5, 5, 6, 7, 8, 16, 22, 23, 23]