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1 Hello friends and welcome to the tutorial on Sets |
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2 |
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3 {{{ Show the slide containing title }}} |
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4 |
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5 {{{ Show the slide containing the outline slide }}} |
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6 |
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7 In this tutorial, we shall learn |
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8 |
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9 * sets |
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10 * operations on sets |
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11 |
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12 Sets are data structures which contain unique elements. In other words, |
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13 duplicates are not allowed in sets. |
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14 |
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15 Lets look at how to input sets. |
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16 type |
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17 :: |
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18 |
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19 a_list = [1, 2, 1, 4, 5, 6, 7] |
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20 a = set(a_list) |
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21 a |
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22 |
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23 We can see that duplicates are removed and the set contains only unique |
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24 elements. |
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25 :: |
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26 |
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27 f10 = set([1, 2, 3, 5, 8]) |
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28 p10 = set([2, 3, 5, 7]) |
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29 |
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30 f10 is the set of fibonacci numbers from 1 to 10. |
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31 p10 is the set of prime numbers from 1 to 10. |
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32 |
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33 Sets can be iterated upon just like lists and tuples. |
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34 :: |
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35 |
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36 for i in f10: |
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37 print i, |
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38 |
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39 prints the elements of f10. |
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40 |
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41 The length and containership check on sets is similar as in lists and tuples. |
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42 :: |
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43 |
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44 len(f10) |
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45 |
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46 shows 5. And |
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47 :: |
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48 |
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49 2 in f10 |
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50 |
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51 prints False |
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52 |
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53 The order in which elements are organised in a set is not to be relied upon |
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54 since sets do not support indexing. Hence, slicing and striding are not valid |
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55 on sets. |
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56 |
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57 Various operations that we do on sets are possible here also. |
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58 The | character stands for union |
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59 :: |
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60 |
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61 f10 | p10 |
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62 |
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63 gives us the union of f10 and p10 |
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64 |
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65 The & character stands for intersection. |
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66 :: |
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67 |
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68 f10 & p10 |
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69 |
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70 gives the intersection |
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71 |
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72 similarly, |
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73 :: |
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74 |
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75 f10 - p10 |
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76 |
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77 gives all the elements that are in f10 but not in p10 |
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78 |
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79 :: |
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80 |
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81 f10 ^ p10 |
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82 |
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83 is all the elements in f10 union p10 but not in f10 intersection p10. In |
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84 mathematical terms, it gives the symmectric difference. |
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85 |
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86 {{{ Pause here and try out the following exercises }}} |
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87 |
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88 %% 1 %% Given a list of marks, marks = [20, 23, 22, 23, 20, 21, 23] |
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89 list all the duplicates |
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90 |
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91 {{{ continue from paused state }}} |
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92 |
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93 Duplicates marks are the marks left out when we remove each element of the |
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94 list exactly one time. |
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95 |
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96 :: |
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97 |
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98 marks = [20, 23, 22, 23, 20, 21, 23] |
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99 marks_set = set(marks) |
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100 for mark in marks_set: |
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101 marks.remove(mark) |
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102 |
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103 # we are now left with only duplicates in the list marks |
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104 duplicates = set(marks) |
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105 |
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106 {{{ Show summary slide }}} |
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107 |
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108 This brings us to the end of the tutorial. |
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109 we have learnt |
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110 |
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111 * How to make sets from lists |
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112 * How to input sets |
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113 * The various similarities with lists like length and containership |
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114 * How to perform union, intersection and symmectric difference operations |
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115 |
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116 {{{ Show the "sponsored by FOSSEE" slide }}} |
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117 |
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118 #[Nishanth]: Will add this line after all of us fix on one. |
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119 This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India |
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120 |
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121 Hope you have enjoyed and found it useful. |
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122 Thankyou |
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123 |
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124 .. Author : Nishanth |
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125 Internal Reviewer 1 : |
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126 Internal Reviewer 2 : |
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127 External Reviewer : |