flow control

Flow Control.ipynb

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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Flow Control"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "a = 5"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Boolean test"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
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   "source": [
    "a == 5"
   ]
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   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
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   "source": [
    "a == 4"
   ]
  },
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   "cell_type": "code",
   "execution_count": 4,
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   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "any number but 0 is true\n",
      "\n",
      "note that if 0 did nothing\n"
     ]
    }
   ],
   "source": [
    "if 0:\n",
    "    print(\"this won't do anything\")\n",
    "if 1:\n",
    "    print(\"any number but 0 is true\")\n",
    "\n",
    "print(\"\\nnote that if 0 did nothing\")\n",
    "# an empty string, list and 0 evaluate to False"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## The concept"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a is equal or less than 5\n"
     ]
    }
   ],
   "source": [
    "if a > 5:\n",
    "    # 4 spaces indentation\n",
    "    print(\"a is bigger then 5\")\n",
    "    \n",
    "else:\n",
    "    print(\"a is equal or less than 5\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a is 5\n"
     ]
    }
   ],
   "source": [
    "if a > 5:\n",
    "    # 4 spaces indentation\n",
    "    print(\"a is bigger then 5\")\n",
    "\n",
    "elif a < 5:\n",
    "    print(\"a is bigger then 5\")\n",
    "\n",
    "else:\n",
    "    print('a is 5')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a is not equal to 4\n"
     ]
    }
   ],
   "source": [
    "if a != 4: # ! evaluate to true if the opposite is correct, is a is not equal to 4\n",
    "    print('a is not equal to 4')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(True, False)"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "a == 5, a == 4 # == checks a condition, does not assign a value!"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Multiple checks, or & and"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a is between 3 and 7\n"
     ]
    }
   ],
   "source": [
    "if a > 3 and a < 7: # both must be true for the statement to occur\n",
    "    print(\"a is between 3 and 7\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a is greater than 3, or less than -5\n"
     ]
    }
   ],
   "source": [
    "if a > 3 or a < -5: # # obly one must be true for the statement to occur\n",
    "    print(\"a is greater than 3, or less than -5\")"
   ]
  }
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