Standard - Closures functions return functions

Standard - Closures functions return functions.ipynb

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      "source": "#  Closures: Functions that return functions\nA closure is any dynamically-generated function returned by another function. The key property is that the returned function has access to the variables in the local namespace where it was created."
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      "source": "def make_watcher():\n    local_call_memory = {}\n\n    def has_been_seen(x):\n        print('Check local_call_memory for x={}'.format(x))\n        if x in local_call_memory:\n            print('x={} was alread stored in local_call_memory for'.format(x))\n            return True\n        else:\n            print('x={} is new, store value'.format(x))\n            local_call_memory[x] = True\n            return False\n\n    print('Bind Function: has_been_seen')\n    return has_been_seen",
      "execution_count": 32,
      "outputs": []
    },
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      "metadata": {
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      "cell_type": "code",
      "source": "watcher = make_watcher()",
      "execution_count": 33,
      "outputs": [
        {
          "output_type": "stream",
          "text": "Bind Function: has_been_seen\n",
          "name": "stdout"
        }
      ]
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    {
      "metadata": {
        "trusted": true,
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      "cell_type": "code",
      "source": "vals = [5, 6, 1, 5, 1, 6, 3, 5]",
      "execution_count": 34,
      "outputs": []
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      "metadata": {
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      "cell_type": "code",
      "source": "[watcher(x) for x in vals]",
      "execution_count": 35,
      "outputs": [
        {
          "output_type": "stream",
          "text": "Check local_call_memory for x=5\nx=5 is new, store value\nCheck local_call_memory for x=6\nx=6 is new, store value\nCheck local_call_memory for x=1\nx=1 is new, store value\nCheck local_call_memory for x=5\nx=5 was alread stored in local_call_memory for\nCheck local_call_memory for x=1\nx=1 was alread stored in local_call_memory for\nCheck local_call_memory for x=6\nx=6 was alread stored in local_call_memory for\nCheck local_call_memory for x=3\nx=3 is new, store value\nCheck local_call_memory for x=5\nx=5 was alread stored in local_call_memory for\n",
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          "execution_count": 35
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        "description": "Standard - Closures functions return functions",
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