diff --git a/r.ipynb b/r.ipynb
new file mode 100644
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+++ b/r.ipynb
@@ -0,0 +1,388 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "d9c9e526",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "<re.Match object; span=(0, 3), match='cat'>\n"
+     ]
+    }
+   ],
+   "source": [
+    "import re\n",
+    "str = 'cat mat bat rat'\n",
+    "output=re.match(r\"c\\w\\w\",str)\n",
+    "\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "ef870eb7",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "<re.Match object; span=(12, 15), match='rat'>\n"
+     ]
+    }
+   ],
+   "source": [
+    "import re\n",
+    "str = 'cat mat bat rat'\n",
+    "output=re.search(r\"r\\w\\w\",str)\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "49f6f805",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['mat', 'man']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Write the regular expression and use proper method which gives output as:- ['mat', 'man'] in str.\n",
+    "import re\n",
+    "str = 'cat mat bat rat man'\n",
+    "out=re.findall(\"m\\w\\w\",str)\n",
+    "print(out)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "1f3284dd",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['Python', 's', 'Programming', '', 'is', 'very', 'easy', 'to', 'learn']\n"
+     ]
+    }
+   ],
+   "source": [
+    "import re\n",
+    "str = \"Python's Programming: is very easy to learn\"\n",
+    "print(re.split(\"\\W\",str))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "id": "2c361dac",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['Python', 'Programming: is very easy to learn']\n"
+     ]
+    }
+   ],
+   "source": [
+    "# output as:- Python Programming: is very easy to learn in str.\n",
+    "import re\n",
+    "str = \"Python's Programming: is very easy to learn\"\n",
+    "print(re.split(\"'s \",str))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "f11c7359",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['peter', 'per', 'picked', 'peck', 'pickled', 'peppers']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Output:- ['peter', 'per', 'picked', 'peck', 'pickled', 'peppers']\n",
+    "import re\n",
+    "str = \"peter giper picked a peck of pickled peppers\"\n",
+    "output=re.findall(r\"p\\w{2,}\\b\",str)\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "b289aed9",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['peter', 'picked', 'peck', 'pickled', 'peppers']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve all words starting with p except 'per' which is not a separate word.\n",
+    "import re\n",
+    "str = \"peter giper picked a peck of pickled peppers\"\n",
+    "\n",
+    "output=re.findall(r\"p\\w{3,}\\b\",str)\n",
+    "\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "id": "cb0ab297",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['8th', '11th']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieves all words starting with a digit.\n",
+    "import re\n",
+    "str = 'The election in delhi will be held on 8th and result for the same will be declared on 11th'\n",
+    "output=re.findall(\"\\d{1,2}\\w\\w\",str)\n",
+    "print(output)\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "id": "1d97ca0b",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['peter', 'giper']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve all words having 5 characters.\n",
+    "import re\n",
+    "str = \"peter giper picked a peck of pickled peppers\"\n",
+    "output=re.findall(r\"\\b\\w{5}\\b\",str)\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "id": "5923bcba",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['Retrieving', 'words', 'having', 'least', 'characters']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve all words having at least 4 characters.\n",
+    "import re\n",
+    "str = \"Retrieving all words having at least 4 characters\"\n",
+    "output=re.findall(r\"\\b\\w{4,}\\b\",str)\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "id": "a4b9892e",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['all', 'words', 'least']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve all words having at characters between 3 to 5 words.\n",
+    "\n",
+    "import re\n",
+    "str = \"Retrieving all words having at least 4 characters\"\n",
+    "output=re.findall(r\"\\b\\w{3,5}\\b\",str)\n",
+    "print(output)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "id": "41da455c",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['8', '11']\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Retrieve only digits from the string.\n",
+    "import re\n",
+    "str = 'The election in delhi will be held on 8 and result for the same will be declared on 11'\n",
+    "out=re.findall(r\"\\b\\d{1,2}\\b\",str)\n",
+    "print(out)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "id": "848fba27",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "<re.Match object; span=(39, 49), match='characters'>\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve last word if starts with c from the given string.\n",
+    "import re\n",
+    "str = \"Retrieving all words having at least 4 characters\"\n",
+    "st1=r\"c\\w{1,}$\"\n",
+    "nstr=re.search(st1,str)\n",
+    "print(nstr)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "id": "46b8e789",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['1234567890']\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve a phone number from the given string.\n",
+    "import re\n",
+    "str = \"Learnbay : 1234567890\"\n",
+    "out=re.findall(r\"\\b\\d{10}\\b\",str)\n",
+    "print(out)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "id": "ea300f1e",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Learnbay : \n"
+     ]
+    }
+   ],
+   "source": [
+    "#Extracs name from the string but not number\n",
+    "import re\n",
+    "str = \"Learnbay : 1234567890\"\n",
+    "st=r\"\\b\\D{1,}\\b\"\n",
+    "nst=\"\".join(re.findall(st,str))\n",
+    "print(nst)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "id": "6d30a8c4",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "anil akhil anant ankur\n"
+     ]
+    }
+   ],
+   "source": [
+    "#Retrieve name starting with 'an' or 'ak'.\n",
+    "import re\n",
+    "str = 'anil akhil anant abhi arun arati arundhati abhijit ankur'\n",
+    "st1=r\"\\ba[n,k]\\w{1,}\\b\"\n",
+    "\n",
+    "nstr=\" \".join(re.findall(st1,str))\n",
+    "print(nstr)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "39b95d37",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.8"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}