32 |
32 |
33 Before we can proceed, start your IPython interpreter with the |
33 Before we can proceed, start your IPython interpreter with the |
34 ``-pylab`` option. |
34 ``-pylab`` option. |
35 |
35 |
36 {{{ start ipython interpreter by issuing command ipython -pylab }}} |
36 {{{ start ipython interpreter by issuing command ipython -pylab }}} |
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37 |
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38 {{{ switch to next slide, Creating dictionary }}} |
37 |
39 |
38 Let us start by creating an empty dictionary, type the following in |
40 Let us start by creating an empty dictionary, type the following in |
39 your IPython interpreter. |
41 your IPython interpreter. |
40 :: |
42 :: |
41 |
43 |
71 extensions |
73 extensions |
72 |
74 |
73 in the interpreter to see the content of the dictionary. Notice that |
75 in the interpreter to see the content of the dictionary. Notice that |
74 in dictionaries the order cannot be predicted and you can see that the |
76 in dictionaries the order cannot be predicted and you can see that the |
75 values are not in the order that we entered in. |
77 values are not in the order that we entered in. |
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78 |
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79 {{{ switch to next slide, accessing elements }}} |
76 |
80 |
77 Like in lists, the elements in a dictionary can be accessed using the |
81 Like in lists, the elements in a dictionary can be accessed using the |
78 index, here the index is the key. Try, |
82 index, here the index is the key. Try, |
79 :: |
83 :: |
80 |
84 |
151 |
155 |
152 {{{ switch to next slide, problem statement for the next solved |
156 {{{ switch to next slide, problem statement for the next solved |
153 exercise }}} |
157 exercise }}} |
154 |
158 |
155 Now let us try to print the data in the dictionary. We can use ``for`` |
159 Now let us try to print the data in the dictionary. We can use ``for`` |
156 loop to iterate. |
160 loop to iterate. Pause here and try to do it yourself. |
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161 |
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162 It can be solved as, |
157 :: |
163 :: |
158 |
164 |
159 for each in extensions.keys(): |
165 for each in extensions.keys(): |
160 print each, "-->", extensions[each] |
166 print each, "-->", extensions[each] |
161 |
167 |
162 |
168 |
163 {{{ switch to next slide, recap }}} |
169 {{{ switch to next slide, summary }}} |
164 |
170 |
165 This brings us to the end of this tutorial, we learned dictionaries |
171 This brings us to the end of this tutorial, we learned dictionaries |
166 and saw how to create an empty dictionary, build a dictionary with |
172 and saw how to create an empty dictionary, build a dictionary with |
167 some data in it, adding data, ``keys()`` and ``values()`` methods, and |
173 some data in it, adding data, ``keys()`` and ``values()`` methods, and |
168 iterating over the dictionaries. |
174 iterating over the dictionaries. |