1_introduction/intro.ipynb

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    "# Basic Python Notes"
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    "在python 2.x中，input会计算字符串中的数学表达式，raw_input是普通的字符串读入\n",
    "\n",
    "在python 3.x中，raw_input和input合体，取消raw_input"
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     "text": [
      "Please enter your name:Andy\n",
      "Andy\n"
     ]
    }
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   "source": [
    "aName = raw_input(\"Please enter your name:\")\n",
    "print aName"
   ]
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     "text": [
      "Please enter a formulation:22+3\n",
      "25\n"
     ]
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   "source": [
    "cal = input(\"Please enter a formulation:\")\n",
    "print cal"
   ]
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     "text": [
      "('Your name in all capitals is', 'ANDY', 'and has length', 4)\n"
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   "source": [
    "print(\"Your name in all capitals is\", aName.upper(), \"and has length\", len(aName))"
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   "source": [
    "## % format operator"
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     "text": [
      "Hi, Andy.\n"
     ]
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   "source": [
    "print(\"Hi, %s.\" % (aName))"
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   "source": [
    "python2中的range返回的是一个列表\n",
    "\n",
    "python3中的range返回的是一个迭代器"
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      "text/plain": [
       "xrange"
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   "source": [
    "type(range(10))"
   ]
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     "data": {
      "text/plain": [
       "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
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   "source": [
    "from six.moves import range\n",
    "type(range(10))\n",
    "# list(type(range(10)))"
   ]
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   "source": [
    "## list comprehension"
   ]
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       "[1, 9, 25, 49, 81]"
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   "source": [
    "sqlist = [x*x for x in range(10) if x%2 != 0]\n",
    "sqlist"
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    "Built-in Collection Data Types\n",
    "\n",
    "list string tuple set dictionary"
   ]
  },
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   "source": [
    "## exceptions"
   ]
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      "Please enter an integer -12\n",
      "Bad Value for square root, using absolute value instead\n",
      "3.46410161514\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "anumber = int(raw_input(\"Please enter an integer \"))\n",
    "try:\n",
    "    print(math.sqrt(anumber))\n",
    "except:\n",
    "    print(\"Bad Value for square root, using absolute value instead\")\n",
    "    print(math.sqrt(abs(anumber)))"
   ]
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   "source": [
    "constructor method \\__init\\__(self,*)\n",
    "\n",
    "\\__str\\__ : convert an object into a string(default, instance address)"
   ]
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   "source": [
    "## 操作符重载\n",
    "\n",
    "override operands: \\__add\\__, \\__eq\\__, "
   ]
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