Python is pass by value or by assignment

Python is pass by assignment.ipynb

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   "source": [
    " According to the offical documentation, Python is [pass by assignment](https://docs.python.org/3/faq/programming.html#how-do-i-write-a-function-with-output-parameters-call-by-reference).\n",
    " It is not `pass by value` nor `pass by reference`. Let me explain:"
   ]
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     "text": [
      "[1, 2, 3]\n"
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   "source": [
    "def modify(lst):\n",
    "    lst = [0,0,0]\n",
    "\n",
    "l = [1,2,3]\n",
    "modify(l)\n",
    "print(l)"
   ]
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   "source": [
    " `lst` is a local variable inside `modify`. It is a copy of the variable `l` but not a copy of the list `[1,2,3]`.\n",
    " If written in code, `lst` is:\n",
    "```python\n",
    "l = [1,2,3]\n",
    "lst = l\n",
    "```"
   ]
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   "source": [
    " You can modify `l` by:"
   ]
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     "text": [
      "[0, 2, 3, 4]\n"
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   "source": [
    "def modify_2(lst):\n",
    "    lst[0] = 0\n",
    "    lst.append(4)\n",
    "\n",
    "l = [1,2,3]\n",
    "modify_2(l)\n",
    "print(l)"
   ]
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   "source": [
    "## Python is not pass by value\n",
    " If this is the case, then `lst` is equivlent of:"
   ]
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      "[1, 2, 3]\n"
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   "source": [
    "l = [1,2,3]\n",
    "lst = l.copy() \n",
    "lst[0] = 0 # any modification to lst does not affect l\n",
    "print(l)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Python is not pass by reference\n",
    " If this is the case, then:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[1, 2, 3]\n"
     ]
    }
   ],
   "source": [
    "def modify(lst):\n",
    "    lst = [0,0,0]\n",
    "\n",
    "l = [1,2,3]\n",
    "modify(l)\n",
    "print(l) #if python is pass by reference, this will print [0,0,0]. But this is not the case."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## What is pass by assginment again?\n",
    " It is marking a copy of a reference to an object.\n",
    "```python\n",
    "l = [1,2,3]\n",
    "lst = l\n",
    "```"
   ]
  }
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