Data commit

Task/Queue-Definition/Python/queue-definition-1.py

@@ -0,0 +1,45 @@
+   class FIFO(object):
+       def __init__(self, *args):
+           self.contents = list(args)
+       def __call__(self):
+           return self.pop()
+       def __len__(self):
+           return len(self.contents)
+       def pop(self):
+           return self.contents.pop(0)
+       def push(self, item):
+           self.contents.append(item)
+       def extend(self,*itemlist):
+           self.contents += itemlist
+       def empty(self):
+           return bool(self.contents)
+       def __iter__(self):
+           return self
+       def next(self):
+           if self.empty():
+               raise StopIteration
+           return self.pop()
+
+if __name__ == "__main__":
+    # Sample usage:
+    f = FIFO()
+    f.push(3)
+    f.push(2)
+    f.push(1)
+    while not f.empty():
+        print f.pop(),
+    # >>> 3 2 1
+    # Another simple example gives the same results:
+    f = FIFO(3,2,1)
+    while not f.empty():
+        print f(),
+    # Another using the default "truth" value of the object
+    # (implicitly calls on the length() of the object after
+    # checking for a __nonzero__ method
+    f = FIFO(3,2,1)
+    while f:
+        print f(),
+    # Yet another, using more Pythonic iteration:
+    f = FIFO(3,2,1)
+    for i in f:
+        print i,

Task/Queue-Definition/Python/queue-definition-2.py

@@ -0,0 +1,15 @@
+class FIFO:  ## NOT a new-style class, must not derive from "object"
+   def __init__(self,*args):
+       self.contents = list(args)
+   def __call__(self):
+       return self.pop()
+   def empty(self):
+       return bool(self.contents)
+   def pop(self):
+       return self.contents.pop(0)
+   def __getattr__(self, attr):
+       return getattr(self.contents,attr)
+   def next(self):
+       if not self:
+           raise StopIteration
+       return self.pop()

Task/Queue-Definition/Python/queue-definition-3.py

@@ -0,0 +1,6 @@
+from collections import deque
+fifo = deque()
+fifo. appendleft(value) # push
+value = fifo.pop()
+not fifo # empty
+fifo.pop() # raises IndexError when empty