Difference between revisions of "Python/C3/Dictionaries/English-timed"
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{| border=1 | {| border=1 | ||
− | + | |'''Time''' | |
− | + | |'''Narration''' | |
+ | |||
|- | |- | ||
− | | | + | | 00:01 |
| Hello friends and Welcome to the spoken tutorial on 'dictionaries'. | | Hello friends and Welcome to the spoken tutorial on 'dictionaries'. | ||
|- | |- | ||
− | | | + | | 00:05 |
| At the end of this tutorial, you will be able to, | | At the end of this tutorial, you will be able to, | ||
− | + | Create dictionaries. | |
− | + | Add and delete data from dictionaries. | |
− | + | Retrieve data from dictionaries. | |
− | + | Check for container-ship of keys. | |
− | + | Iterating over elements. | |
− | + | ||
|- | |- | ||
− | | | + | | 00:20 |
| Before beginning this tutorial,we would suggest you to complete the tutorial on "Basic datatypes and operators". | | Before beginning this tutorial,we would suggest you to complete the tutorial on "Basic datatypes and operators". | ||
|- | |- | ||
− | | | + | | 00:27 |
| A dictionary in general, is designed to look up for meanings of words. | | A dictionary in general, is designed to look up for meanings of words. | ||
|- | |- | ||
− | | | + | |00:35 |
| Similarly, Python dictionary is also designed to look up for a specific key and retrieve the corresponding value. | | Similarly, Python dictionary is also designed to look up for a specific key and retrieve the corresponding value. | ||
|- | |- | ||
− | | | + | |00:43 |
|Dictionaries are data structures that provide key-value mappings. | |Dictionaries are data structures that provide key-value mappings. | ||
|- | |- | ||
− | | | + | |00:47 |
|Dictionaries are similar to lists except that instead of the values having integer indexes, dictionaries have keys or strings as indexes. | |Dictionaries are similar to lists except that instead of the values having integer indexes, dictionaries have keys or strings as indexes. | ||
|- | |- | ||
− | | | + | | 00:58 |
| We start our ipython interpreter as, ipython | | We start our ipython interpreter as, ipython | ||
|- | |- | ||
− | | | + | | 01:07 |
| Let us start by creating an empty dictionary. | | Let us start by creating an empty dictionary. | ||
|- | |- | ||
− | | | + | |01:12 |
| Type the following in your IPython interpreter,mt underscore dict = closing curly brackets | | Type the following in your IPython interpreter,mt underscore dict = closing curly brackets | ||
|- | |- | ||
− | | | + | | 01:25 |
− | | Notice that unlike lists, curly braces are used to define a | + | | Notice that unlike lists, curly braces are used to define a dictionary |
|- | |- | ||
− | | | + | |01:33 |
| Now let us see how to create a non-empty dictionary, | | Now let us see how to create a non-empty dictionary, | ||
|- | |- | ||
− | | | + | |01:37 |
|so type extensions = open curly brackets in single quotes jpg colon 'JPEG Image' comma 'py' colon 'Python script' comma | |so type extensions = open curly brackets in single quotes jpg colon 'JPEG Image' comma 'py' colon 'Python script' comma | ||
'html' colon 'Html document' comma pdf colon Portable Document Format close curly brackets | 'html' colon 'Html document' comma pdf colon Portable Document Format close curly brackets | ||
− | |||
|- | |- | ||
− | | | + | | 02:08 |
| Notice that each key-value pair is separated by a comma. | | Notice that each key-value pair is separated by a comma. | ||
|- | |- | ||
− | | | + | | 02:17 |
− | | and each key | + | | and each key value are separated using a colon. |
|- | |- | ||
− | | | + | | 02:23 |
| Here, we have defined four entries in the dictionary extensions. | | Here, we have defined four entries in the dictionary extensions. | ||
|- | |- | ||
− | | | + | |02:29 |
|The keys are jpg comma py comma html comma and pdf. | |The keys are jpg comma py comma html comma and pdf. | ||
|- | |- | ||
− | | | + | |02:36 |
|Simply type,extensions in the interpreter to see the content of the dictionary. | |Simply type,extensions in the interpreter to see the content of the dictionary. | ||
|- | |- | ||
− | | | + | |02:40 |
|So type extensions. | |So type extensions. | ||
|- | |- | ||
− | | | + | | 02:45 |
| Notice that, in dictionaries, the order cannot be predicted and you can see that the values are not in the order that we entered in. | | Notice that, in dictionaries, the order cannot be predicted and you can see that the values are not in the order that we entered in. | ||
|- | |- | ||
− | | | + | | 02:53 |
| Like lists, the elements in a dictionary can be accessed using the index, here the index is the key. | | Like lists, the elements in a dictionary can be accessed using the index, here the index is the key. | ||
|- | |- | ||
− | | | + | |03:06 |
− | | We type, print extensions | + | | We type, print extensions in closing brackets in single quotes jpg. |
|- | |- | ||
− | | | + | | 03:25 |
− | | It printed JPEG Image. And now type print extensions within square brackets zip. | + | |NOW It printed JPEG Image. And now type print extensions within square brackets zip. |
|- | |- | ||
− | | | + | | 03:42 |
| Well it gave us an error, saying that the key 'zip' is not in the dictionary. | | Well it gave us an error, saying that the key 'zip' is not in the dictionary. | ||
|- | |- | ||
− | | | + | |03:48 |
− | | | + | |So Pause here for some time and try few more keys. |
|- | |- | ||
− | | | + | |03:52 |
| Also try jpg in capital letters. | | Also try jpg in capital letters. | ||
|- | |- | ||
− | | | + | |03:58 |
− | |<continue from paused state | + | |<continue from paused state Well that was about creating dictionaries, now how do we add or delete items? |
|- | |- | ||
− | | | + | |04:09 |
− | | We can add new items into dictionaries as, | + | | We can add new items into dictionaries as, |
|- | |- | ||
− | | | + | |04:13 |
− | |Type extensions within square brackets | + | |Type extensions within square brackets in single quotes cpp is equal to in single quotes C++ then code. |
|- | |- | ||
− | | | + | | 04:36 |
− | | and delete items using the | + | | and delete items using the del keyword as, type del space extensions and in square brackets and single quotes pdf. |
|- | |- | ||
− | | | + | | 04:51 |
| Let us check the content of the dictionary now, | | Let us check the content of the dictionary now, | ||
|- | |- | ||
− | | | + | |04:54 |
|So type extensions. | |So type extensions. | ||
|- | |- | ||
− | | | + | | 04:57 |
| So the changes have been made. | | So the changes have been made. | ||
|- | |- | ||
− | | | + | |04:59 |
− | | | + | |let us try one more thing, type extensions within square brackets and in single quotes cpp is equal to in single quote C++ and source code. then type again extensions. |
|- | |- | ||
− | | | + | | 05:21 |
| As you can see, it neither added a new thing nor gave an error, but it simply replaced the existing value with the new one. | | As you can see, it neither added a new thing nor gave an error, but it simply replaced the existing value with the new one. | ||
|- | |- | ||
− | | | + | |05:29 |
|Now let us learn how to check if a particular key is present in the dictionary. | |Now let us learn how to check if a particular key is present in the dictionary. | ||
|- | |- | ||
− | | | + | |05:33 |
− | | For that we can use the method | + | | For that we can use the method in, |
|- | |- | ||
− | | | + | |05:37 |
|So type within single quotes py in extensions. | |So type within single quotes py in extensions. | ||
|- | |- | ||
− | | | + | |05:45 |
− | |Then type | + | |Then type odt in extensions. |
|- | |- | ||
− | | | + | | 05:53 |
− | | It will return | + | | It will return True if the key is found in the dictionary, and will return False if key is not present. |
|- | |- | ||
− | | | + | |06:00 |
| Note that we can check only for container-ship of keys in dictionaries and not values. | | Note that we can check only for container-ship of keys in dictionaries and not values. | ||
|- | |- | ||
− | | | + | | 06:07 |
| Now let us see how to retrieve the keys and values. | | Now let us see how to retrieve the keys and values. | ||
|- | |- | ||
− | | | + | |06:10 |
− | | We can use the method | + | | We can use the method keys() for getting a list of the keys in a particular dictionary and the method values() for getting a list of values. |
|- | |- | ||
− | | | + | | 06:20 |
− | | Let us try them, type extensions dot | + | | Let us try them, type extensions dot key closing brackets. |
|- | |- | ||
− | | | + | | 06:31 |
− | | It returned the | + | | It returned the list of keys in the dictionary extensions. |
|- | |- | ||
− | | | + | |06:35 |
| And now the other one is extensions dot values and closing brackets. | | And now the other one is extensions dot values and closing brackets. | ||
|- | |- | ||
− | | | + | | 06:42 |
− | | It returned the | + | | It returned the list of values in the dictionary. |
|- | |- | ||
− | | | + | |06:45 |
|Pause the video here, try out the following exercise and resume the video. | |Pause the video here, try out the following exercise and resume the video. | ||
|- | |- | ||
− | | | + | | 06:49 |
| Print the keys and values in the dictionary one by one. | | Print the keys and values in the dictionary one by one. | ||
|- | |- | ||
− | | | + | |06:54 |
− | | Switch to terminal for solution. | + | |Now Switch to terminal for solution. |
|- | |- | ||
− | | | + | |06:58 |
− | |Type for each in extensions dot keys closing brackets colon then, | + | |Type for each in extensions dot keys closing brackets colon then, print each comma within double quotes hyphen hyphen greater symbol, extensions and in square brackets each. |
− | + | ||
|- | |- | ||
− | | | + | | 07:35 |
| This brings us to the end of this tutorial. | | This brings us to the end of this tutorial. | ||
|- | |- | ||
− | | | + | |07:39 |
− | |In this tutorial, we have | + | |In this tutorial, we have learn't to, |
|- | |- | ||
− | | | + | |07:41 |
− | | | + | |Create dictionaries namely -- - empty dictionaries - dictionaries with data. |
|- | |- | ||
− | | | + | |07:45 |
− | | | + | |Access elements in the dictionaries using the keys. |
|- | |- | ||
− | | | + | |07:49 |
− | | | + | |Add elements to a dictionary by assigning a key value. |
+ | |||
|- | |- | ||
− | | | + | |07:55 |
− | | | + | |Delete elements from a dictionary by using the function del |
|- | |- | ||
− | | | + | |08:00 |
− | | | + | |Retrieve the keys and values by using the methods .keys() and.values() respectively. |
|- | |- | ||
− | | | + | |08:06 |
− | | | + | |Iterate over elements of a dictionary using a for loop. |
|- | |- | ||
− | | | + | | 08:11 |
| Here are some self assessment questions for you to solve | | Here are some self assessment questions for you to solve | ||
|- | |- | ||
− | | | + | |08:15 |
− | | | + | |First one, Container-ship of values can be checked in a python dictionary - true or false. |
|- | |- | ||
− | | | + | |08:22 |
− | | | + | |Second one is, Consider the python dictionary x is equal to within curly brackets 'a' colon ['a','b','c'], 'b' colon (1, 2, 3), 1 colon then again another curly braces 1 colon 'one' comma 2 colon 'two' comma 10 colon within curly brackets 10 colon 'ten', 11 colon 'eleven' and close the curly brackets. |
|- | |- | ||
− | | | + | |08:52 |
| What will the following code return? | | What will the following code return? | ||
|- | |- | ||
− | | | + | |08:57 |
− | | | + | |(1, 2, 3) in x.values(). True. False |
|- | |- | ||
− | | | + | |09:05 |
|Then container-ship of values cannot be checked in dictionaries | |Then container-ship of values cannot be checked in dictionaries | ||
|- | |- | ||
− | | | + | |09:10 |
| The dictionary is invalid | | The dictionary is invalid | ||
|- | |- | ||
− | | | + | | 09:13 |
| So Lets look at the answers, | | So Lets look at the answers, | ||
|- | |- | ||
− | | | + | |09:16 |
− | | | + | |The answer of first one, False. |
|- | |- | ||
− | | | + | |09:19 |
| Container-ship of only keys can be checked in a python dictionary. | | Container-ship of only keys can be checked in a python dictionary. | ||
|- | |- | ||
− | | | + | |09:27 |
− | | | + | |Second one is, True |
|- | |- | ||
− | | | + | | 09:31 |
| Hope you have enjoyed this tutorial and found it useful. | | Hope you have enjoyed this tutorial and found it useful. | ||
|- | |- | ||
− | | | + | |09:35 |
|Thank you! | |Thank you! | ||
|} | |} |
Latest revision as of 16:38, 20 February 2017
Time | Narration |
00:01 | Hello friends and Welcome to the spoken tutorial on 'dictionaries'. |
00:05 | At the end of this tutorial, you will be able to,
Create dictionaries. Add and delete data from dictionaries. Retrieve data from dictionaries. Check for container-ship of keys. Iterating over elements. |
00:20 | Before beginning this tutorial,we would suggest you to complete the tutorial on "Basic datatypes and operators". |
00:27 | A dictionary in general, is designed to look up for meanings of words. |
00:35 | Similarly, Python dictionary is also designed to look up for a specific key and retrieve the corresponding value. |
00:43 | Dictionaries are data structures that provide key-value mappings. |
00:47 | Dictionaries are similar to lists except that instead of the values having integer indexes, dictionaries have keys or strings as indexes. |
00:58 | We start our ipython interpreter as, ipython |
01:07 | Let us start by creating an empty dictionary. |
01:12 | Type the following in your IPython interpreter,mt underscore dict = closing curly brackets |
01:25 | Notice that unlike lists, curly braces are used to define a dictionary |
01:33 | Now let us see how to create a non-empty dictionary, |
01:37 | so type extensions = open curly brackets in single quotes jpg colon 'JPEG Image' comma 'py' colon 'Python script' comma
'html' colon 'Html document' comma pdf colon Portable Document Format close curly brackets |
02:08 | Notice that each key-value pair is separated by a comma. |
02:17 | and each key value are separated using a colon. |
02:23 | Here, we have defined four entries in the dictionary extensions. |
02:29 | The keys are jpg comma py comma html comma and pdf. |
02:36 | Simply type,extensions in the interpreter to see the content of the dictionary. |
02:40 | So type extensions. |
02:45 | Notice that, in dictionaries, the order cannot be predicted and you can see that the values are not in the order that we entered in. |
02:53 | Like lists, the elements in a dictionary can be accessed using the index, here the index is the key. |
03:06 | We type, print extensions in closing brackets in single quotes jpg. |
03:25 | NOW It printed JPEG Image. And now type print extensions within square brackets zip. |
03:42 | Well it gave us an error, saying that the key 'zip' is not in the dictionary. |
03:48 | So Pause here for some time and try few more keys. |
03:52 | Also try jpg in capital letters. |
03:58 | <continue from paused state Well that was about creating dictionaries, now how do we add or delete items? |
04:09 | We can add new items into dictionaries as, |
04:13 | Type extensions within square brackets in single quotes cpp is equal to in single quotes C++ then code. |
04:36 | and delete items using the del keyword as, type del space extensions and in square brackets and single quotes pdf. |
04:51 | Let us check the content of the dictionary now, |
04:54 | So type extensions. |
04:57 | So the changes have been made. |
04:59 | let us try one more thing, type extensions within square brackets and in single quotes cpp is equal to in single quote C++ and source code. then type again extensions. |
05:21 | As you can see, it neither added a new thing nor gave an error, but it simply replaced the existing value with the new one. |
05:29 | Now let us learn how to check if a particular key is present in the dictionary. |
05:33 | For that we can use the method in, |
05:37 | So type within single quotes py in extensions. |
05:45 | Then type odt in extensions. |
05:53 | It will return True if the key is found in the dictionary, and will return False if key is not present. |
06:00 | Note that we can check only for container-ship of keys in dictionaries and not values. |
06:07 | Now let us see how to retrieve the keys and values. |
06:10 | We can use the method keys() for getting a list of the keys in a particular dictionary and the method values() for getting a list of values. |
06:20 | Let us try them, type extensions dot key closing brackets. |
06:31 | It returned the list of keys in the dictionary extensions. |
06:35 | And now the other one is extensions dot values and closing brackets. |
06:42 | It returned the list of values in the dictionary. |
06:45 | Pause the video here, try out the following exercise and resume the video. |
06:49 | Print the keys and values in the dictionary one by one. |
06:54 | Now Switch to terminal for solution. |
06:58 | Type for each in extensions dot keys closing brackets colon then, print each comma within double quotes hyphen hyphen greater symbol, extensions and in square brackets each. |
07:35 | This brings us to the end of this tutorial. |
07:39 | In this tutorial, we have learn't to, |
07:41 | Create dictionaries namely -- - empty dictionaries - dictionaries with data. |
07:45 | Access elements in the dictionaries using the keys. |
07:49 | Add elements to a dictionary by assigning a key value. |
07:55 | Delete elements from a dictionary by using the function del |
08:00 | Retrieve the keys and values by using the methods .keys() and.values() respectively. |
08:06 | Iterate over elements of a dictionary using a for loop. |
08:11 | Here are some self assessment questions for you to solve |
08:15 | First one, Container-ship of values can be checked in a python dictionary - true or false. |
08:22 | Second one is, Consider the python dictionary x is equal to within curly brackets 'a' colon ['a','b','c'], 'b' colon (1, 2, 3), 1 colon then again another curly braces 1 colon 'one' comma 2 colon 'two' comma 10 colon within curly brackets 10 colon 'ten', 11 colon 'eleven' and close the curly brackets. |
08:52 | What will the following code return? |
08:57 | (1, 2, 3) in x.values(). True. False |
09:05 | Then container-ship of values cannot be checked in dictionaries |
09:10 | The dictionary is invalid |
09:13 | So Lets look at the answers, |
09:16 | The answer of first one, False. |
09:19 | Container-ship of only keys can be checked in a python dictionary. |
09:27 | Second one is, True |
09:31 | Hope you have enjoyed this tutorial and found it useful. |
09:35 | Thank you! |