gistfile1.txt

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      "Inclusion in a `list`\n",
      "---------------------\n",
      "True\n",
      "False\n",
      "\n",
      "Inclusion in a `tuple`\n",
      "----------------------\n",
      "Error: 'tuple' object does not support item assignment\n",
      "True\n",
      "Error: argument of type 'int' is not iterable\n",
      "True\n",
      "False\n",
      "\n",
      "Inclusion in a `dict`\n",
      "---------------------\n",
      "True\n",
      "False\n",
      "\n",
      "Inclusion in a `set`\n",
      "--------------------\n",
      "True\n",
      "True\n",
      "True\n",
      "False\n"
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    "# Inclusion and comparisons\n",
    "# =========================\n",
    "\n",
    "# Inclusion\n",
    "# ~~~~~~~~~\n",
    "# Checking for \"inclusion\" means you're checking\n",
    "# if a value is included in a collection. There\n",
    "# are several different types of collections in\n",
    "# python, including `list`s, `tuple`s, `dict`s,\n",
    "# and `set`s.\n",
    "\n",
    "# You check for inclusion using the \"in\" keyword\n",
    "# as in \"x in y\"\n",
    "\n",
    "print \"Inclusion in a `list`\"\n",
    "print \"---------------------\"\n",
    "print 1 in [1, 2, 3]  # True\n",
    "print 1 in [2, 3, 4]  # False\n",
    "\n",
    "\n",
    "print \"\\nInclusion in a `tuple`\"\n",
    "print \"----------------------\"\n",
    "\n",
    "# A tuple is a lot like a list, but is \"immutable\",\n",
    "# so you can't change it once it's been created\n",
    "my_tuple = (1, 2, 3)\n",
    "try:\n",
    "    my_tuple[0] = 4  # Error\n",
    "except Exception as e:\n",
    "    print 'Error: {}'.format(e)\n",
    "\n",
    "print 1 in (1, 2, 3)  # True\n",
    "try:\n",
    "    print 1 in (1)  # Error, parens don't make the tuple, commas do\n",
    "except Exception as e:\n",
    "    print 'Error: {}'.format(e)\n",
    "print 1 in (1,)  # True, notice the comma after the 1\n",
    "print 1 in (2, 3, 4)  # False\n",
    "\n",
    "\n",
    "print \"\\nInclusion in a `dict`\"\n",
    "print \"---------------------\"\n",
    "\n",
    "# We're looking at the _keys_ here, not the values\n",
    "print 1 in {\n",
    "    1: 'one',\n",
    "    2: 'two',\n",
    "    3: 'three'}  # True\n",
    "print 1 in {\n",
    "    'one': 1,\n",
    "    'two': 2,\n",
    "    'three': 3}  # False, 1 is a value but not a key\n",
    "\n",
    "\n",
    "print \"\\nInclusion in a `set`\"\n",
    "print \"--------------------\"\n",
    "\n",
    "# `set`s look like `dict`s with just the keys and no\n",
    "# values. Under the hood, looking up a value in a set\n",
    "# is faster than looking up a value in a list\n",
    "\n",
    "print 1 in { 1 }  # True\n",
    "print 1 in { 1, 2, 3 }  # True\n",
    "print 1 in { 'one', 1, 1, 1, 'one' }  # True\n",
    "print 1 in { 'one', 2, 3 }  # False"
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      "Comparing `list`s\n",
      "-----------------\n",
      "False\n",
      "True\n",
      "False\n",
      "\n",
      "Comparing `list`s\n",
      "-----------------\n",
      "False\n",
      "True\n",
      "False\n",
      "False\n",
      "\n",
      "Comparing `dict`s\n",
      "-----------------\n",
      "False\n",
      "True\n",
      "False\n",
      "False\n",
      "\n",
      "Comparing `set`s\n",
      "----------------\n",
      "False\n",
      "True\n",
      "False\n",
      "1\n",
      "1\n",
      "True\n"
     ]
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   "source": [
    "# Comparison\n",
    "# ~~~~~~~~~~\n",
    "\n",
    "print \"Comparing `list`s\"\n",
    "print \"-----------------\"\n",
    "\n",
    "# For two `list`s to be equal, they must\n",
    "# have the same values in the same order\n",
    "print 1 == [1, 2, 3]  # False, different types\n",
    "print [1, 2, 3] == [1, 2, 3]  # True\n",
    "print [4, 2, 3] == [2, 3, 4]  # False, different order\n",
    "\n",
    "\n",
    "print \"\\nComparing `list`s\"\n",
    "print \"-----------------\"\n",
    "\n",
    "# For two `tuple`s to be equal, they must\n",
    "# also have the same values in the same order.\n",
    "# `list`s and `tuple`s are not equivalent, even\n",
    "# if they have the same values in the same order.\n",
    "print 1 == (1, 2, 3)  # False\n",
    "print (1, 2, 3) == (1, 2, 3) # True\n",
    "print (4, 2, 3) == (2, 3, 4)  # False, different order\n",
    "print (1, 2, 3) == [1, 2, 3]  # False, different types\n",
    "\n",
    "\n",
    "print \"\\nComparing `dict`s\"\n",
    "print \"-----------------\"\n",
    "\n",
    "# For two `dict`s to be equal, they must have the\n",
    "# same keys _and_ values. Order of the keys doesn't\n",
    "# matter.\n",
    "print 1 == {\n",
    "    1: 'one',\n",
    "    2: 'two',\n",
    "    3: 'three'}  # False, different types\n",
    "print {\n",
    "    1: 'one',\n",
    "    2: 'two',\n",
    "    3: 'three'\n",
    "} == {\n",
    "    3: 'three',\n",
    "    2: 'two',\n",
    "    1: 'one'}  # True, order doesn't matter\n",
    "print {\n",
    "    1: 'one',\n",
    "    2: 'two',\n",
    "    3: 'three'\n",
    "} == {\n",
    "    1: 'uno',\n",
    "    2: 'dos',\n",
    "    3: 'tres'}  # False, values are not the same\n",
    "print {\n",
    "    1: 'one',\n",
    "    2: 'two',\n",
    "    3: 'three'\n",
    "} == {\n",
    "    1: 'uno',\n",
    "    2: 'dos'}  # False, different keys\n",
    "\n",
    "\n",
    "print \"\\nComparing `set`s\"\n",
    "print \"----------------\"\n",
    "\n",
    "# For two `set`s to be equal, they must have the\n",
    "# same values. Order doesn't matter.\n",
    "print 1 == {1, 2, 3}  # False, different types\n",
    "print { 1, 2, 3 } == { 3, 2, 1 }  # True, order doesn't matter\n",
    "print { 1, 2, 3 } == { 1, 2 }  # False, different values\n",
    "\n",
    "# Duplicate values are removed in a set, a value\n",
    "# can only be present once.\n",
    "print len({ 1 })  # 1\n",
    "print len({ 1, 1, 1, 1, 1, 1, })  # Also 1\n",
    "print { 1 } == { 1, 1, 1, 1, 1, 1, }  # True, duplicates are removed\n"
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