add some codes

codes/dqn_cnn/memory.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+# coding=utf-8
+'''
+@Author: John
+@Email: johnjim0816@gmail.com
+@Date: 2020-06-11 09:42:44
+@LastEditor: John
+@LastEditTime: 2020-06-11 15:50:33
+@Discription: 
+@Environment: python 3.7.7
+'''
+from collections import namedtuple
+import random
+
+
+                      
+class ReplayBuffer(object):
+
+    def __init__(self, capacity):
+        self.capacity = capacity
+        self.buffer = []
+        self.position = 0
+        self.Transition = namedtuple('Transition',
+                        ('state', 'action', 'next_state', 'reward'))
+
+    def push(self, *args):
+        """Saves a transition."""
+        if len(self.buffer) < self.capacity:
+            self.buffer.append(None)
+        self.buffer[self.position] = self.Transition(*args)
+        self.position = (self.position + 1) % self.capacity
+
+    def sample(self, batch_size):
+        return random.sample(self.buffer, batch_size)
+
+    def __len__(self):
+        return len(self.buffer)