{
"metadata": {
"name": "data_structures"
},
"nbformat": 2,
"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"source": [
"### Tuple ###",
"denoted with parentheses"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t = (12,-1)",
"print type(t)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"<type 'tuple'>"
]
}
],
"prompt_number": 1
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print isinstance(t,tuple)",
"print len(t)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"True",
"2"
]
}
],
"prompt_number": 2
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t = (12,\"monty\",True,-1.23e6)",
"print t[1]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"monty"
]
}
],
"prompt_number": 3
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print t[-1]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"-1230000.0"
]
}
],
"prompt_number": 4
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t[-2:] # get the last two elements, return as a tuple"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 5,
"text": [
"(True, -1230000.0)"
]
}
],
"prompt_number": 5
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"x = (True) ; print type(x)",
"x = (True,) ; print type(x)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"<type 'bool'>",
"<type 'tuple'>"
]
}
],
"prompt_number": 6
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"type(()), len(())"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 7,
"text": [
"(tuple, 0)"
]
}
],
"prompt_number": 7
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"type((,))"
],
"language": "python",
"outputs": [
{
"ename": "SyntaxError",
"evalue": "invalid syntax (<ipython-input-8-21eccbe9b1de>, line 1)",
"output_type": "pyerr",
"traceback": [
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-8-21eccbe9b1de>\"\u001b[0;36m, line \u001b[0;32m1\u001b[0m\n\u001b[0;31m type((,))\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m invalid syntax\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "markdown",
"source": [
"single-element tuples look like `(element,)`"
]
},
{
"cell_type": "markdown",
"source": [
"cannot change a tuple",
"but you can create new one with concatenation"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t[2] = False"
],
"language": "python",
"outputs": [
{
"ename": "TypeError",
"evalue": "'tuple' object does not support item assignment",
"output_type": "pyerr",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mTypeError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m/Users/jbloom/Classes/python-bootcamp/DataFiles_and_Notebooks/02_AdvancedDataStructures/<ipython-input-9-9365ccccf007>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mt\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m2\u001b[0m\u001b[0;34m]\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mFalse\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m: 'tuple' object does not support item assignment"
]
}
],
"prompt_number": 9
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t[0:2], False, t[3:]"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 10,
"text": [
"((12, 'monty'), False, (-1230000.0,))"
]
}
],
"prompt_number": 10
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## the above it ",
"## not what we wanted... need to concatenate",
"t[0:2] + False + t[3:]"
],
"language": "python",
"outputs": [
{
"ename": "TypeError",
"evalue": "can only concatenate tuple (not \"bool\") to tuple",
"output_type": "pyerr",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mTypeError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m/Users/jbloom/Classes/python-bootcamp/DataFiles_and_Notebooks/02_AdvancedDataStructures/<ipython-input-11-73d4c94ec2bf>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m 1\u001b[0m \u001b[0;31m## the above it\u001b[0m\n\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 2\u001b[0m \u001b[0;31m## not what we wanted... need to concatenate\u001b[0m\n\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mt\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m0\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;36m2\u001b[0m\u001b[0;34m]\u001b[0m \u001b[0;34m+\u001b[0m \u001b[0mFalse\u001b[0m \u001b[0;34m+\u001b[0m \u001b[0mt\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m3\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m: can only concatenate tuple (not \"bool\") to tuple"
]
}
],
"prompt_number": 11
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"y = t[0:2] + (False,) + t[3:] ; print y"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(12, 'monty', False, -1230000.0)"
]
}
],
"prompt_number": 12
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t*2"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 13,
"text": [
"(12, 'monty', True, -1230000.0, 12, 'monty', True, -1230000.0)"
]
}
],
"prompt_number": 13
},
{
"cell_type": "markdown",
"source": [
"### List ###",
"#### denoted with a brackets ####"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v = [1,2,3] ; print len(v), type(v)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"3 <type 'list'>"
]
}
],
"prompt_number": 14
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v[0:2]"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 15,
"text": [
"[1, 2]"
]
}
],
"prompt_number": 15
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v = [\"eggs\",\"spam\",-1,(\"monty\",\"python\"),[-1.2,-3.5]]",
"len(v)"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 16,
"text": [
"5"
]
}
],
"prompt_number": 16
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v[0] =\"green egg\"",
"v[1] += \",love it.\"",
"v[-1]"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 17,
"text": [
"[-1.2, -3.5]"
]
}
],
"prompt_number": 17
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v[-1][1] = None ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"['green egg', 'spam,love it.', -1, ('monty', 'python'), [-1.2, None]]"
]
}
],
"prompt_number": 18
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v = v[2:] ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[-1, ('monty', 'python'), [-1.2, None]]"
]
}
],
"prompt_number": 19
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"# let's make a proto-array out of nested lists",
"vv = [ [1,2], [3,4] ]"
],
"language": "python",
"outputs": [],
"prompt_number": 20
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print len(vv)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"2"
]
}
],
"prompt_number": 21
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"determinant = vv[0][0]*vv[1][1] - vv[0][1]*vv[1][0]",
"print determinant"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"-2"
]
}
],
"prompt_number": 22
},
{
"cell_type": "markdown",
"source": [
"the main point here: lists are **changeable**",
"",
"[back to slides]"
]
},
{
"cell_type": "markdown",
"source": [
"### List ###",
"#### lists can be extended, appended, and popped ####"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v = [1,2,3]",
"v.append(4)",
"v.append([-5]) ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[1, 2, 3, 4, [-5]]"
]
}
],
"prompt_number": 23
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v = v[:4]",
"w = ['elderberries', 'eggs']",
"v + w"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 24,
"text": [
"[1, 2, 3, 4, 'elderberries', 'eggs']"
]
}
],
"prompt_number": 24
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.extend(w) ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[1, 2, 3, 4, 'elderberries', 'eggs']"
]
}
],
"prompt_number": 25
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.pop()"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 26,
"text": [
"'eggs'"
]
}
],
"prompt_number": 26
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[1, 2, 3, 4, 'elderberries']"
]
}
],
"prompt_number": 27
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.pop(0) ; print v ## pop the first element"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[2, 3, 4, 'elderberries']"
]
}
],
"prompt_number": 28
},
{
"cell_type": "markdown",
"source": [
" * `.append()`: adds a new element",
" * `.extend()`: concatenates a list/element",
" * `.pop()`: remove an element"
]
},
{
"cell_type": "markdown",
"source": [
"#### lists can be searched, sorted, & counted ####"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v = [1,3, 2, 3, 4, 'elderberries']",
"v.sort() ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[1, 2, 3, 3, 4, 'elderberries']"
]
}
],
"prompt_number": 29
},
{
"cell_type": "markdown",
"source": [
"`reverse` is a keyword of the `.sort()` method"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.sort(reverse=True) ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"['elderberries', 4, 3, 3, 2, 1]"
]
}
],
"prompt_number": 30
},
{
"cell_type": "markdown",
"source": [
"`.sort()` changes the the list in place "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.index(4) ## lookup the index of the entry 4"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 31,
"text": [
"1"
]
}
],
"prompt_number": 31
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.index(3)"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 32,
"text": [
"2"
]
}
],
"prompt_number": 32
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.count(3)"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 33,
"text": [
"2"
]
}
],
"prompt_number": 33
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.insert(0,\"it's full of stars\") ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[\"it's full of stars\", 'elderberries', 4, 3, 3, 2, 1]"
]
}
],
"prompt_number": 34
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"v.remove(1) ; print v"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[\"it's full of stars\", 'elderberries', 4, 3, 3, 2]"
]
}
],
"prompt_number": 35
},
{
"cell_type": "markdown",
"source": [
"[back]"
]
},
{
"cell_type": "markdown",
"source": [
"### List ###",
"#### iteration ####"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"a = ['cat', 'window', 'defenestrate']",
"for x in a:",
" print x, len(x)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"cat 3",
"window 6",
"defenestrate 12"
]
}
],
"prompt_number": 37
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"for i,x in enumerate(a):",
" print i, x, len(x)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"0 cat 3",
"1 window 6",
"2 defenestrate 12"
]
}
],
"prompt_number": 38
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"for x in a:",
" print x,"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"cat window defenestrate"
]
}
],
"prompt_number": 39
},
{
"cell_type": "markdown",
"source": [
"The syntax for iteration is... ",
"",
" for variable_name in iterable:",
" # do something with variable_name"
]
},
{
"cell_type": "markdown",
"source": [
"The `range()` function"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"x = range(4) ; print x",
"total = 0",
"for val in range(4):",
" total += val",
" print \"By adding \" + str(val) + \\",
" \" the total is now \" + str(total)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[0, 1, 2, 3]",
"By adding 0 the total is now 0",
"By adding 1 the total is now 1",
"By adding 2 the total is now 3",
"By adding 3 the total is now 6"
]
}
],
"prompt_number": 41
},
{
"cell_type": "markdown",
"source": [
"",
"`range`([`start`,] `stop`[, `step`])",
"\u2192 list of integers"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"total = 0",
"for val in range(1,10,2):",
" total += val",
" print \"By adding \" + str(val) + \\",
" \" the total is now \" + str(total)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"By adding 1 the total is now 1",
"By adding 3 the total is now 4",
"By adding 5 the total is now 9",
"By adding 7 the total is now 16",
"By adding 9 the total is now 25"
]
}
],
"prompt_number": 42
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"a = ['Mary', 'had', 'a', 'little', 'lamb']",
"for i in range(len(a)):",
" print i, a[i]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"0 Mary",
"1 had",
"2 a",
"3 little",
"4 lamb"
]
}
],
"prompt_number": 43
},
{
"cell_type": "markdown",
"source": [
"### Sets ###",
"#### denoted with a curly braces ####"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"{1,2,3,\"bingo\"}"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 45,
"text": [
"set(['bingo', 1, 2, 3])"
]
}
],
"prompt_number": 45
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print type({1,2,3,\"bingo\"})"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"<type 'set'>"
]
}
],
"prompt_number": 47
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print type({})"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"<type 'dict'>"
]
}
],
"prompt_number": 48
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print type(set())"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"<type 'set'>"
]
}
],
"prompt_number": 50
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"set(\"spamIam\")"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 51,
"text": [
"set(['a', 'p', 's', 'm', 'I'])"
]
}
],
"prompt_number": 51
},
{
"cell_type": "markdown",
"source": [
"sets have unique elements. They can be",
"compared, differenced, unionized, etc."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"a = set(\"sp\"); b = set(\"am\"); print a ; print b"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"set(['p', 's'])",
"set(['a', 'm'])"
]
}
],
"prompt_number": 52
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"c = set([\"a\",\"m\"])",
"c == b"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 53,
"text": [
"True"
]
}
],
"prompt_number": 53
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\"p\" in a"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 54,
"text": [
"True"
]
}
],
"prompt_number": 54
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\"ps\" in a"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 55,
"text": [
"False"
]
}
],
"prompt_number": 55
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"q = set(\"spamIam\")",
"a.issubset(q)"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 57,
"text": [
"True"
]
}
],
"prompt_number": 57
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"a | b"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 58,
"text": [
"set(['a', 'p', 's', 'm'])"
]
}
],
"prompt_number": 58
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"q - (a | b)"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 59,
"text": [
"set(['I'])"
]
}
],
"prompt_number": 59
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"q & (a | b)"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 60,
"text": [
"set(['a', 'p', 's', 'm'])"
]
}
],
"prompt_number": 60
},
{
"cell_type": "markdown",
"source": [
"Like lists, we can use as (unordered) buckets",
"`.pop()` gives us a random element"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# this is pretty volitile...wont be the same",
"# order on all machines",
"for i in q & (a | b):",
" print i, "
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a p s m"
]
}
],
"prompt_number": 62
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"q.remove(\"a\")"
],
"language": "python",
"outputs": [],
"prompt_number": 63
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"q.pop()"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 64,
"text": [
"'p'"
]
}
],
"prompt_number": 64
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print q.pop()",
"print q.pop()"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"s",
"m"
]
}
],
"prompt_number": 65
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print q.pop()"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"I"
]
}
],
"prompt_number": 66
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"q.pop()"
],
"language": "python",
"outputs": [
{
"ename": "KeyError",
"evalue": "'pop from an empty set'",
"output_type": "pyerr",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mKeyError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m/Users/jbloom/Classes/python-bootcamp/DataFiles_and_Notebooks/02_AdvancedDataStructures/<ipython-input-68-16da542f89c5>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mq\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mpop\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mKeyError\u001b[0m: 'pop from an empty set'"
]
}
],
"prompt_number": 68
},
{
"cell_type": "markdown",
"source": [
"[back]"
]
},
{
"cell_type": "markdown",
"source": [
"### 4 ways to make a Dictionary ###"
]
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"# number 1...you've seen this",
"d = {\"favorite cat\": None, \"favorite spam\": \"all\"}"
],
"language": "python",
"outputs": [],
"prompt_number": 69
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# number 2",
"d = dict(one = 1, two=2,cat = 'dog') ; print d"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"{'cat': 'dog', 'two': 2, 'one': 1}"
]
}
],
"prompt_number": 70
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# number 3 ... just start filling in items/keys",
"d = {} # empty dictionary",
"d['cat'] = 'dog'",
"d['one'] = 1",
"d['two'] = 2",
"d"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 71,
"text": [
"{'cat': 'dog', 'one': 1, 'two': 2}"
]
}
],
"prompt_number": 71
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# number 4... start with a list of tuples",
"mylist = [(\"cat\",\"dog\"), (\"one\",1),(\"two\",2)]",
"print dict(mylist)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"{'one': 1, 'two': 2, 'cat': 'dog'}"
]
}
],
"prompt_number": 72
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"dict(mylist) == d"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 73,
"text": [
"True"
]
}
],
"prompt_number": 73
},
{
"cell_type": "markdown",
"source": [
"#### Dictionaries: they can be complicated (in a good way) ####"
]
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"d = {\"favorite cat\": None, \"favorite spam\": \"all\"}"
],
"language": "python",
"outputs": [],
"prompt_number": 75
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"d = {'favorites': {'cat': None, 'spam': 'all'}, \\",
" 'least favorite': {'cat': 'all', 'spam': None}}",
"print d['least favorite']['cat']"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"all"
]
}
],
"prompt_number": 78
},
{
"cell_type": "markdown",
"source": [
"remember: the backslash (\\) allows you to across break lines. Not technically needed when defining a dictionary or list"
]
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"phone_numbers = {'family': [('mom','642-2322'),('dad','534-2311')],\\",
" 'friends': [('Billy','652-2212')]}"
],
"language": "python",
"outputs": [],
"prompt_number": 79
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"for group_type in ['friends','family']:",
" print \"Group \" + group_type + \":\"",
" for info in phone_numbers[group_type]:",
" print \" \",info[0], info[1]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Group friends:",
" Billy 652-2212",
"Group family:",
" mom 642-2322",
" dad 534-2311"
]
}
],
"prompt_number": 80
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# this will return a list, but you dont know in what order! ",
"phone_numbers.keys()"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 81,
"text": [
"['friends', 'family']"
]
}
],
"prompt_number": 81
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"phone_numbers.values()"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 82,
"text": [
"[[('Billy', '652-2212')], [('mom', '642-2322'), ('dad', '534-2311')]]"
]
}
],
"prompt_number": 82
},
{
"cell_type": "markdown",
"source": [
"`.keys()` and `.values()`: are called `methods` on dictionaries"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"for group_type in phone_numbers.keys():",
" print \"Group \" + group_type + \":\"",
" for info in phone_numbers[group_type]:",
" print \" \",info[0], info[1]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Group friends:",
" Billy 652-2212",
"Group family:",
" mom 642-2322",
" dad 534-2311"
]
}
],
"prompt_number": 83
},
{
"cell_type": "markdown",
"source": [
"we cannot ensure ordering here of the groups"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"groups = phone_numbers.keys()",
"groups.sort()",
"for group_type in groups:",
" print \"Group \" + group_type + \":\"",
" for info in phone_numbers[group_type]:",
" print \" \",info[0], info[1]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Group family:",
" mom 642-2322",
" dad 534-2311",
"Group friends:",
" Billy 652-2212"
]
}
],
"prompt_number": 84
},
{
"cell_type": "markdown",
"source": [
"`.iteritems()` is a handy method,",
"returning key,value pairs with each iteration"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"for group_type, vals in phone_numbers.iteritems():",
" print \"Group \" + group_type + \":\"",
" for info in vals:",
" print \" \",info[0], info[1]"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Group friends:",
" Billy 652-2212",
"Group family:",
" mom 642-2322",
" dad 534-2311"
]
}
],
"prompt_number": 85
},
{
"cell_type": "markdown",
"source": [
"Some examples of getting values:"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"phone_numbers['co-workers']"
],
"language": "python",
"outputs": [
{
"ename": "KeyError",
"evalue": "'co-workers'",
"output_type": "pyerr",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mKeyError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m/Users/jbloom/Classes/python-bootcamp/DataFiles_and_Notebooks/02_AdvancedDataStructures/<ipython-input-86-92d1a5b9b960>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mphone_numbers\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;34m'co-workers'\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mKeyError\u001b[0m: 'co-workers'"
]
}
],
"prompt_number": 86
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"phone_numbers.has_key('co-workers')"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 87,
"text": [
"False"
]
}
],
"prompt_number": 87
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print phone_numbers.get('co-workers')"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"None"
]
}
],
"prompt_number": 88
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"phone_numbers.get('friends') == phone_numbers['friends']"
],
"language": "python",
"outputs": [
{
"output_type": "pyout",
"prompt_number": 89,
"text": [
"True"
]
}
],
"prompt_number": 89
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print phone_numbers.get('co-workers',\"all alone\")"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"all alone"
]
}
],
"prompt_number": 90
},
{
"cell_type": "markdown",
"source": [
"#### setting values ####",
"",
"you can edit the values of keys and also `.pop()` & `del` to remove certain keys"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# add to the friends list",
"phone_numbers['friends'].append((\"Marsha\",\"232-1121\"))",
"print phone_numbers"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"{'friends': [('Billy', '652-2212'), ('Marsha', '232-1121')], 'family': [('mom', '642-2322'), ('dad', '534-2311')]}"
]
}
],
"prompt_number": 91
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## billy's number changed",
"phone_numbers['friends'][0][1] = \"532-1521\""
],
"language": "python",
"outputs": [
{
"ename": "TypeError",
"evalue": "'tuple' object does not support item assignment",
"output_type": "pyerr",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mTypeError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m/Users/jbloom/Classes/python-bootcamp/DataFiles_and_Notebooks/02_AdvancedDataStructures/<ipython-input-92-564c1535cc4d>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m 1\u001b[0m \u001b[0;31m## billy's number changed\u001b[0m\n\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 2\u001b[0;31m \u001b[0mphone_numbers\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;34m'friends'\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m0\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m1\u001b[0m\u001b[0;34m]\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m\"532-1521\"\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mTypeError\u001b[0m: 'tuple' object does not support item assignment"
]
}
],
"prompt_number": 92
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"phone_numbers['friends'][0] = (\"Billy\",\"532-1521\")"
],
"language": "python",
"outputs": [],
"prompt_number": 93
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"## I lost all my friends preparing for this Python class",
"phone_numbers['friends'] = [] # sets this to an empty list"
],
"language": "python",
"outputs": [],
"prompt_number": 94
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## remove the friends key altogether",
"print phone_numbers.pop('friends')"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"[]"
]
}
],
"prompt_number": 95
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print phone_numbers"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"{'family': [('mom', '642-2322'), ('dad', '534-2311')]}"
]
}
],
"prompt_number": 96
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"del phone_numbers['family']"
],
"language": "python",
"outputs": [],
"prompt_number": 97
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print phone_numbers"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"{}"
]
}
],
"prompt_number": 98
},
{
"cell_type": "markdown",
"source": [
"`.update()` method is very handy, like `.append()` for lists"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"phone_numbers.update({\"friends\": [(\"Billy's Brother, Bob\", \"532-1521\")]})",
"print phone_numbers"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"{'friends': [(\"Billy's Brother, Bob\", '532-1521')]}"
]
}
],
"prompt_number": 99
},
{
"cell_type": "markdown",
"source": [
"[back]"
]
},
{
"cell_type": "code",
"collapsed": true,
"input": [],
"language": "python",
"outputs": []
}
]
}
]
}