2-2 变量.ipynb

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   "cell_type": "code",
   "execution_count": 1,
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   "source": [
    "import tensorflow as tf"
   ]
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    "x = tf.Variable([1,2])\n",
    "a = tf.constant([3,3])\n",
    "# 增加一个减法op\n",
    "sub = tf.subtract(x,a)\n",
    "# 增加一个加法op\n",
    "add = tf.add(a,sub)\n",
    "\n",
    "# 全局变量初始化\n",
    "init = tf.global_variables_initializer()"
   ]
  },
  {
   "cell_type": "code",
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     "text": [
      "<bound method Variable.value of <tf.Variable 'Variable_1:0' shape=(2,) dtype=int32_ref>>\n",
      "[-2 -1]\n",
      "[1 2]\n"
     ]
    }
   ],
   "source": [
    "with tf.Session() as sess:\n",
    "    sess.run(init)\n",
    "    print(x.value)\n",
    "    print(sess.run(sub))\n",
    "    print(sess.run(add))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "0\n",
      "1\n",
      "2\n",
      "3\n",
      "4\n",
      "5\n"
     ]
    }
   ],
   "source": [
    "# 创建一个变量，初始化为0\n",
    "state = tf.Variable(0, name='counter')\n",
    "# 创建一个op\n",
    "new_value = tf.add(state,1)\n",
    "# 赋值op\n",
    "update = tf.assign(state,new_value)\n",
    "# 初始化全局变量\n",
    "init = tf.global_variables_initializer()\n",
    "\n",
    "# 变量初始化为0，循环更新并打印\n",
    "with tf.Session() as sess:\n",
    "    sess.run(init)\n",
    "    print(sess.run(state))\n",
    "    for _ in range(5):\n",
    "        sess.run(update)\n",
    "        print(sess.run(state))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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