keyword_only.ipynb

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   "source": [
    "__In the below example, `c` & `d` are keyword-only parameters as they follow * in the function definition. And `a` & `b` can be  positional or keyword parameters. And d has default value of `40`.__"
   ]
  },
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   "cell_type": "code",
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   "metadata": {},
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   "source": [
    "def func(a, b, *, c, d=40):\n",
    "    print(f\"a:{a}, b:{b}, c:{c}, d:{d}\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "__In the function call `func(10, 20, 30)`, arguments `10` & `20` are mapped to `a` and `b` by position. The value for `c` is passed as a keyword argument. And `d` gets the default value of `40`.__"
   ]
  },
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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
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     "text": [
      "a:10, b:20, c:30, d:40\n"
     ]
    }
   ],
   "source": [
    "func(10, 20, c=30)"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "__`a` and `b` can be positional or keyword. So the function call `func(a=10, b=20, c=30)` works fine where the arguments a, b, and c are passed as keyword argument and d get the default value 40.__"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a:10, b:20, c:30, d:40\n"
     ]
    }
   ],
   "source": [
    "func(a=10, b=20, c=30)"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "__The function call `func(10, 20)` raise TypeError because func expects two keyword-only parameters `c` and `d`. But we are not passing keyword argument for c. Note that `d` gets default value `40` as defined in the function definition__."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "func() missing 1 required keyword-only argument: 'c'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-4-f34a1c662efd>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mfunc\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m10\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m20\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: func() missing 1 required keyword-only argument: 'c'"
     ]
    }
   ],
   "source": [
    "func(10, 20)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "__The above explanation holds good for this example as well. The only difference is we are calling func with keyword arguments for `a` and `b` instead of positional arguments.__"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "func() missing 1 required keyword-only argument: 'c'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-5-abca81b19a87>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mfunc\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0ma\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m10\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mb\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m20\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: func() missing 1 required keyword-only argument: 'c'"
     ]
    }
   ],
   "source": [
    "func(a=10, b=20)"
   ]
  }
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