{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 1\n",
"Given an array, find out the product of its element using recursion.\n",
"- Input: [1, 2, 3, 4, 5] \n",
"- Output: 120"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"120"
]
},
"execution_count": 1,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def product(arr):\n",
" \"\"\"\n",
" calculates the product of all the numbers in array\n",
" \"\"\"\n",
" if len(arr) == 0:\n",
" return 1\n",
" else:\n",
" return len(arr) * product(arr[1:])\n",
"\n",
"product([1, 2, 3, 4, 5])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 2\n",
"Given a string, write a function `reverse` which accepts a string and returns a new string in reverse.\n",
"- Input: reverse(\"Hello\")\n",
"- Output: \"olleH\""
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"'olleH'"
]
},
"execution_count": 2,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def reverse(string):\n",
" \"\"\"\n",
" returns the reverse of a string\n",
" \"\"\"\n",
" if len(string) == 0:\n",
" return \"\"\n",
" return string[-1] + reverse(string[:-1])\n",
"\n",
"reverse(\"Hello\")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 3\n",
"Given a string, write a function `reverse` to check whether the string is palindrome. \n",
"Note: You must use `recursion` for this problem.\n",
"- Input1: reverse(\"malayalam\") \n",
"- Output1: True\n",
"- Input2: reverse(\"hello\")\n",
"- Output2: False"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"True"
]
},
"execution_count": 3,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def reverse(string):\n",
" \"\"\"\n",
" returns the reverse of a string\n",
" \"\"\"\n",
" if len(string) == 0:\n",
" return \"\"\n",
" return string[-1] + reverse(string[:-1])\n",
"\n",
"string = \"malayalam\"\n",
"string == reverse(string)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 4\n",
"Given a nested array, write a function `flatten` to return a flatlist\n",
"- Input: [[2, 3, [4]]]\n",
"- Output: [2, 3, 4]"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"[2, 3, 4]"
]
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def flatten(arr):\n",
" \"\"\"\n",
" returns the flattened array.\n",
" \"\"\"\n",
" result = []\n",
" for element in arr:\n",
" if type(element) is list:\n",
" result.extend(flatten(element))\n",
" else:\n",
" result.append(element)\n",
" return result\n",
"\n",
"flatten([[2, 3, [4]]])\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 5\n",
"Given a word list, write a function `capitalize_first` to capitalize the first letter of each string in the array. Note, you must use recursion for this problem.\n",
"- Input: capitalize([\"hello\", \"world\"])\n",
"- Output: [\"Hello\", \"World]"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"['Hello', 'World']"
]
},
"execution_count": 5,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def capitalize_first(arr):\n",
" \"\"\"\n",
" converts the first letter of all the elements into uppercase.\n",
" \"\"\"\n",
" result = []\n",
" if len(arr) == 0:\n",
" return result\n",
" result.append(arr[0][0].upper() + arr[0][1:])\n",
" return result + capitalize_first(arr[1:])\n",
"\n",
"capitalize_first([\"hello\", \"world\"])"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 6\n",
"Given a `.json` object, write a function `string_convert` which takes an object and finds all the values which are numbers and converts them into a string.\n",
"- Input: {\n",
" \"num\" : 1,\n",
" \"data\": {\n",
" \"value\" : 8,\n",
" \"jam\" : {\n",
" \"english\": 50\n",
" }\n",
" }\n",
"}\n",
"- Output: {\n",
" \"num\" : \"1\",\n",
" \"data\": {\n",
" \"value\" : \"8\",\n",
" \"jam\" : {\n",
" \"english\": \"50\"\n",
" }\n",
" }\n",
"}"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"{'num': '1', 'data': {'value': '8', 'jam': {'english': '50'}}}"
]
},
"execution_count": 6,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def string_convert(obj):\n",
" \"\"\"\n",
" converts all the integer values inside of an object into a string.\n",
" \"\"\"\n",
" for element in obj:\n",
" if type(obj[element]) is int:\n",
" obj[element] = str(obj[element])\n",
" elif type(obj[element]) is dict:\n",
" obj[element] = string_convert(obj[element])\n",
"\n",
" return obj\n",
"\n",
"string_convert({\n",
" \"num\" : 1,\n",
" \"data\": {\n",
" \"value\" : 8,\n",
" \"jam\" : {\n",
" \"english\": 50\n",
" }\n",
" }\n",
"})\n",
"\n",
"\n",
" \n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Problem 7\n",
"Given a `.json` object, write a function `fetch_str` which takes the object and finds all the keys that have string values. Note, you must use `recursion` for this problem.\n",
"- Input: {\"Hello\": \"World\",\n",
" \"England\": {\n",
" \"London\": \"Heathrow\",\n",
" \"Oxford\":100,\n",
" \"Stanford\": {\n",
" \"France\": \"Paris\",\n",
" \"Germany\": {\n",
" \"Berlin\": \"TU Berlin\",\n",
" \"Frankfurt\": 1000\n",
" }\n",
" }\n",
" },\n",
" \"India\": 1}\n",
"- Output: [\"Hello\", \"London\", \"France\", \"Berlin\"] "
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"['Hello', 'London', 'France', 'Berlin']"
]
},
"execution_count": 7,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"def fetch_str(obj):\n",
" \"\"\"\n",
" Returns keys with integer values.\n",
" \"\"\"\n",
" result = []\n",
" for element in obj:\n",
" if type(obj[element]) is str:\n",
" result.append(element)\n",
" if type(obj[element]) is dict:\n",
" result.extend(fetch_str(obj[element]))\n",
" return result\n",
"\n",
"fetch_str({\"Hello\": \"World\",\n",
" \"England\": {\n",
" \"London\": \"Heathrow\",\n",
" \"Oxford\":100,\n",
" \"Stanford\": {\n",
" \"France\": \"Paris\",\n",
" \"Germany\": {\n",
" \"Berlin\": \"TU Berlin\",\n",
" \"Frankfurt\": 1000\n",
" }\n",
" }\n",
" },\n",
" \"India\": 1})"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
}
],
"metadata": {
"interpreter": {
"hash": "40d3a090f54c6569ab1632332b64b2c03c39dcf918b08424e98f38b5ae0af88f"
},
"kernelspec": {
"display_name": "Python 3.8.3 ('base')",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
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