07_If&else.ipynb

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    "Key takeaways:\n",
    "- Programming controls and decision-making require the programmer to specify conditions that the program will evaluate.\n",
    "- Controls allow non-sequential execution of comments and are specified using keywords such as if and else in many programming languages.\n",
    "- An example of how an if statement works in Python is given, where a condition is checked using the if statement and a block of code is executed if it is true.\n",
    "- The conditions that follow the if keyword are called Boolean expressions and are either true or false.\n",
    "- Boolean expressions are formed with the help of comparison, identity, and membership operators, such as ==, !=, <, >, in, and not in."
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    "# if and loops Part 1\n",
    " # Desicion making and loops are the most important part of programming\n",
    "\n",
    "# if statement\n",
    "# if statement is used to check the condition and execute the code if the condition is true \n",
    "# if the condition is false then the code will not be executed \n"
   ]
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    "# the if statment is written as follows\n",
    "\n",
    "dna = input(\"Enter the DNA sequence: \")\n",
    "\n",
    "if \"n\" in dna:\n",
    "  nbases = dna.count(\"n\")\n",
    "  print(\"The number of n bases is undefined: \", nbases)\n"
   ]
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       "True"
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    "# Boolean expression \n",
    "# Boolean expression is an expression that is either true or false\n",
    "# Boolean expression is used in if statement to check the condition\n",
    "# Boolean expression is written as follows\n",
    "\n",
    "# ==  equal to\n",
    "# !=  not equal to\n",
    "# >   greater than\n",
    "# <   less than\n",
    "# >=  greater than or equal to\n",
    "# <=  less than or equal to\n",
    "\n",
    "# for example\n",
    "5 > 3 # this is a boolean expression and it is true\n"
   ]
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       "False"
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    "\n",
    "len(\"ATGATGATG\") > 10 # this is a boolean expression and it is false"
   ]
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       "True"
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     "execution_count": 5,
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   "source": [
    "\"A\" < \"G\""
   ]
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    "# Membership operator\n",
    "# Membership operator is used to check if a value is present in a sequence\n",
    "# Membership operator is written as follows\n",
    "\n",
    "# in\n",
    "# not in\n",
    "\n",
    "# for example\n",
    "\n",
    "\"ATG\" in \"ATGATGATG\" # this is a membership operator and it is true\n",
    "\n",
    "    "
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       "True"
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   "source": [
    "# not in    \n",
    "\"ATG\" not in \"AGAGAG\" # this is a membership operator and it is false\n"
   ]
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   "execution_count": 8,
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      "text/plain": [
       "False"
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     "execution_count": 8,
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   "source": [
    "# is Operator\n",
    "# is operator is used to check if two variables are pointing to the same object\n",
    "# is operator is written as follows\n",
    "\n",
    "# is\n",
    "# is not\n",
    "\n",
    "# for example\n",
    "\n",
    "dna = \"ATGATGATG\"\n",
    "dna2 = dna\n",
    "dna3 = \"ATGATGATGA\"\n",
    "\n",
    "dna is dna3 # this is a is operator and it is true\n"
   ]
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      "The number of n bases is zero\n"
     ]
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    "dna = input(\"Enter the DNA sequence: \")\n",
    "\n",
    "if \"n\" in dna or \"N\" in dna:\n",
    "    nbases = dna.count(\"n\") + dna.count(\"N\")\n",
    "    print(\"The number of n bases is undefined: \", nbases)\n",
    "else:\n",
    "    print(\"The number of n bases is zero\")\n"
   ]
  }
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