Python/C3/Dictionaries/English-timed - Revision history

PoojaMoolya at 11:08, 20 February 2017

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Gaurav at 10:05, 10 July 2014

2014-07-10T10:05:23Z

Gaurav at 10:05, 10 July 2014

2014-07-10T10:05:02Z

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Sneha at 09:40, 28 March 2013

2013-03-28T09:40:07Z

Sneha at 07:10, 28 March 2013

2013-03-28T07:10:32Z

Sneha at 06:53, 28 March 2013

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Sneha at 06:52, 28 March 2013

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Sneha at 06:50, 28 March 2013

2013-03-28T06:50:19Z

Minal: Created page with '{| border=1 !Timing !Narration |- | 0:01 | Hello friends and Welcome to the spoken tutorial on 'dictionaries'. |- | 0:05 | At the end of this tutorial, you will be able to, # …'

2013-01-02T12:10:37Z

Created page with '{| border=1 !Timing !Narration |- | 0:01 | Hello friends and Welcome to the spoken tutorial on 'dictionaries'. |- | 0:05 | At the end of this tutorial, you will be able to, # …'

New page

{| border=1
!Timing
!Narration
|-
| 0:01
| Hello friends and Welcome to the spoken tutorial on 'dictionaries'.

|-
| 0:05
| 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.

|-
| 0:20
| Before beginning this tutorial,we would suggest you to complete the tutorial on "Basic datatypes and operators".

|-
| 0:27
| A dictionary in general, is designed to look up for meanings of words.

|-
|0:35
| Similarly, Python dictionary is also designed to look up for a specific key and retrieve the corresponding value.

|-
|0:43
|Dictionaries are data structures that provide key-value mappings.

|-
|0:47
|Dictionaries are similar to lists except that instead of the values having integer indexes, dictionaries have keys or strings as indexes.

|-
| 0:58
| We start our ipython interpreter as, ipython

|-
| 1:07
| Let us start by creating an empty dictionary.

|-
|1:12
| Type the following in your IPython interpreter,mt underscore dict = closing curly brackets

|-
| 1:25
| Notice that unlike lists, curly braces are used to define a <tt>dictionary</tt>.

|-
|1:33
| Now let us see how to create a non-empty dictionary,

|-
|1:37
|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

|-
| 2:08
| Notice that each key-value pair is separated by a comma.

|-
| 2:17
| and each key and value are separated using a colon.

|-
| 2:23
| Here, we have defined four entries in the dictionary extensions.

|-
|2:29
|The keys are jpg comma py comma html comma and pdf.

|-
|2:36
|Simply type,extensions in the interpreter to see the content of the dictionary.

|-
|2:40
|So type extensions.

|-
| 2:45
| 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.

|-
| 2:53
| Like lists, the elements in a dictionary can be accessed using the index, here the index is the key.

|-
|3:06
| We type, print extensions within closing brackets and single quotes jpg.

|-
| 3:25
| It printed JPEG Image. And now type print extensions within square brackets zip.

|-
| 3:42
| Well it gave us an error, saying that the key 'zip' is not in the dictionary.

|-
|3:48
|<nowiki>So Pause here for some time and try few more keys.

|-
|3:52
| Also try jpg in capital letters.

|-
|3:58
|<continue from paused state> Well that was about creating dictionaries, now how do we add or delete items.

|-
|4:09
| We can add new items into dictionaries as,</nowiki>

|-
|4:13
|Type extensions within square brackets and single quotes cpp is equal to in single quotes C++ then code.

|-
| 4:36
| and delete items using the <tt>del</tt> keyword as, type del space extensions within square brackets and single quotes pdf.

|-
| 4:51
| Let us check the content of the dictionary now,

|-
|4:54
|So type extensions.

|-
| 4:57
| So the changes have been made.

|-
|4:59
| Now 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.

|-
| 5:21
| 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.

|-
|5:29
|Now let us learn how to check if a particular key is present in the dictionary.

|-
|5:33
| For that we can use the method <tt>in</tt>,

|-
|5:37
|So type within single quotes py in extensions.

|-
|5:45
|Then type within single quotes odt in extensions.

|-
| 5:53
| It will return <tt>True</tt> if the key is found in the dictionary, and will return <tt>False</tt> if key is not present.

|-
|6:00
| Note that we can check only for container-ship of keys in dictionaries and not values.

|-
| 6:07
| Now let us see how to retrieve the keys and values.

|-
|6:10
| We can use the method <tt>keys()</tt> for getting a list of the keys in a particular dictionary and the method <tt>values()</tt> for getting a list of values.

|-
| 6:20
| Let us try them, type extensions dot keys closing brackets.

|-
| 6:31
| It returned the <tt>list</tt> of keys in the dictionary extensions.

|-
|6:35
| And now the other one is extensions dot values and closing brackets.

|-
| 6:42
| It returned the <tt>list</tt> of values in the dictionary.

|-
|6:45
|Pause the video here, try out the following exercise and resume the video.

|-
| 6:49
| Print the keys and values in the dictionary one by one.

|-
|6:54
| Switch to terminal for solution.

|-
|6:58
|Type for each in extensions dot keys closing brackets colon then,
print each comma within double quotes hyphen hyphen greater symbol, extensions and within closing brackets each.

|-
| 7:35
| This brings us to the end of this tutorial.

|-
|7:39
|In this tutorial, we have learnt to,

|-
|7:41
|1. Create dictionaries namely -- - empty dictionaries - dictionaries with data.

|-
|7:45
|2. Access elements in the dictionaries using the keys.

|-
|7:49
|3. Add elements to a dictionary by assigning a key value.
|-
|7:55
|4. Delete elements from a dictionary by using the function <tt>del</tt>.

|-
|8:00
|5. Retrieve the keys and values by using the methods <tt>.keys()</tt> and <tt>.values()</tt> respectively.

|-
|8:06
|6. Iterate over elements of a dictionary using a <tt>for</tt> loop.

|-
| 8:11
| Here are some self assessment questions for you to solve

|-
|8:15
|1. First one, Container-ship of values can be checked in a python dictionary - true or false.

|-
|8:22
|2. 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.

|-
|8:52
| What will the following code return?

|-
|8:57
|<br/> <tt>(1, 2, 3) in x.values()</tt>. True. False

|-
|9:05
|Then container-ship of values cannot be checked in dictionaries

|-
|9:10
| The dictionary is invalid

|-
| 9:13
| So Lets look at the answers,

|-
|9:16
|1.The answer of first one, False.

|-
|9:19
| Container-ship of only keys can be checked in a python dictionary.

|-
|9:27
|2. Second one is, True

|-
| 9:31
| Hope you have enjoyed this tutorial and found it useful.

|-
|9:35
|Thank you!

|}

@@ Line 10: / Line 10: @@
 | 00:05
 | At the end of this tutorial, you will be able to,
 Create dictionaries.
-# Create dictionaries.
+Add and delete data from dictionaries.
-# Add and delete data from dictionaries.
+Retrieve data from dictionaries.
-# Retrieve data from dictionaries.
+Check for container-ship of keys.
-# Check for container-ship of keys.
+Iterating  over elements.
-# Iterating  over elements.
 |-
@@ Line 213: / Line 212: @@
 |-
 |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.
-    print each comma within double quotes hyphen hyphen greater symbol, extensions and  in square   brackets each.
 |-
@@ Line 226: / Line 224: @@
 |-
 |07:41
-|1. Create dictionaries namely -- - empty dictionaries - dictionaries with data.
+|Create dictionaries namely -- - empty dictionaries - dictionaries with data.
 |-
 |07:45
-|2. Access elements in the dictionaries using the keys.
+|Access elements in the dictionaries using the keys.
 |-
 |07:49
-|3. Add elements to a dictionary by assigning a key value.
+|Add elements to a dictionary by assigning a key value.
 |-
 |07:55
-|4. Delete elements from a dictionary by using the function del
+|Delete elements from a dictionary by using the function del
 |-
 |08:00
-|5. Retrieve the keys and values by using the methods .keys() and.values() respectively.
+|Retrieve the keys and values by using the methods .keys() and.values() respectively.
 |-
 |08:06
-|6. Iterate over elements of a dictionary using a for loop.
+|Iterate over elements of a dictionary using a for loop.
 |-
@@ Line 254: / Line 252: @@
 |-
 |08:15
-|1. First one, Container-ship of values can be checked in a python dictionary - true or false.
+|First one, Container-ship of values can be checked in a python dictionary - true or false.
 |-
 |08:22
-|2. 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.
+|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.
 |-
@@ Line 282: / Line 280: @@
 |-
 |09:16
-|1.The answer of first one, False.
+|The answer of first one, False.
 |-
@@ Line 290: / Line 288: @@
 |-
 |09:27
-|2. Second one is, True
+|Second one is, True
 |-

@@ Line 50: / Line 50: @@
 |-
 | 1:25
-| Notice that unlike lists, curly braces are used to define a <tt>dictionary</tt>.
+| Notice that unlike lists, curly braces are used to define a dictionary
 |-

@@ Line 63: / Line 63: @@
 'html'  colon  'Html document' comma pdf  colon  Portable Document Format close curly brackets
 |-
 | 02:08

@@ Line 69: / Line 69: @@
 |-
 |  2:17
-| and each key and value are separated using a colon.
+| and each key  value are separated using a colon.
 |-
@@ Line 97: / Line 97: @@
 |-
 |3:06
-| We type, print extensions within closing brackets and single quotes jpg.
+| We type, print extensions  in closing brackets in single quotes jpg.
 |-
 | 3:25
-| 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.
 |-
@@ Line 117: / Line 117: @@
 |-
 |3:58
-|<continue from paused state Well that was about creating dictionaries, now how do we add or delete items.
+|<continue from paused state Well that was about creating dictionaries, now how do we add or delete items?
 |-
@@ Line 125: / Line 125: @@
 |-
 |4:13
-|Type extensions within square brackets and single quotes cpp is equal to in single quotes C++ then code.
+|Type extensions within square brackets in single quotes cpp is equal to in single quotes C++ then code.
 |-
 |  4:36
-| and delete items using the  del  keyword as, type del space extensions within square brackets and single quotes pdf.
+| and delete items using the  del  keyword as, type del space extensions and in square brackets and single quotes pdf.
 |-
@@ Line 145: / Line 145: @@
 |-
 |4:59
-| Now 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.
+|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.
 |-
@@ Line 165: / Line 165: @@
 |-
 |5:45
-|Then type within single quotes odt in extensions.
+|Then type  odt in extensions.
 |-
@@ Line 185: / Line 185: @@
 |-
 | 6:20
-| Let us try them, type extensions dot keys closing brackets.
+| Let us try them, type extensions dot key closing brackets.
 |-
@@ Line 209: / Line 209: @@
 |-
 |6:54
-| Switch to terminal for solution.
+|Now Switch to terminal for solution.
 |-
 |6:58
 |Type for each in extensions dot keys closing brackets colon then,
-     print each comma within double quotes hyphen hyphen greater symbol, extensions and within closing brackets each.
+     print each comma within double quotes hyphen hyphen greater symbol, extensions and  in square   brackets each.
 |-

@@ Line 109: / Line 109: @@
 |-
 |3:48
-|<nowiki>So Pause here for some time and try few more keys.
+|So Pause here for some time and try few more keys.
 |-
@@ Line 121: / Line 121: @@
 |-
 |4:09
-| We can add new items into dictionaries as,</nowiki>
+| We can add new items into dictionaries as,
 |-
@@ Line 257: / Line 257: @@
 |-
 |8:22
-|2. 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.
+|2. 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.
 |-

@@ Line 129: / Line 129: @@
 |-
 |  4:36
-| and delete items using the <tt>del</tt> keyword as, type del space extensions within square brackets and single quotes pdf.
+| and delete items using the  del  keyword as, type del space extensions within square brackets and single quotes pdf.
 |-
@@ Line 157: / Line 157: @@
 |-
 |5:33
-| For that we can use the method <tt>in</tt>,
+| For that we can use the method in,
 |-
@@ Line 169: / Line 169: @@
 |-
 | 5:53
-| It will return <tt>True</tt> if the key is found in the dictionary, and will return <tt>False</tt> if key is not present.
+| It will return True  if the key is found in the dictionary, and will return False if key is not present.
 |-
@@ Line 181: / Line 181: @@
 |-
 |6:10
-| We can use the method <tt>keys()</tt> for getting a list of the keys in a particular dictionary and the method <tt>values()</tt> for getting a list of values.
+| 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.
 |-
@@ Line 189: / Line 189: @@
 |-
 |  6:31
-| It returned the <tt>list</tt> of keys in the dictionary extensions.
+| It returned the list of keys in the dictionary extensions.
 |-
@@ Line 197: / Line 197: @@
 |-
 | 6:42
-| It returned the <tt>list</tt> of values in the dictionary.
+| It returned the list of values in the dictionary.
 |-
@@ Line 222: / Line 222: @@
 |-
 |7:39
-|In this tutorial, we have learnt to,
+|In this tutorial, we have learn't to,
 |-
@@ Line 237: / Line 237: @@
 |-
 |7:55
-|4. Delete elements from a dictionary by using the function <tt>del</tt>.
+|4. Delete elements from a dictionary by using the function del
 |-
 |8:00
-|5. Retrieve the keys and values by using the methods <tt>.keys()</tt> and <tt>.values()</tt> respectively.
+|5. Retrieve the keys and values by using the methods .keys() and.values() respectively.
 |-
 |8:06
-|6. Iterate over elements of a dictionary using a <tt>for</tt> loop.
+|6. Iterate over elements of a dictionary using a for loop.
 |-
@@ Line 265: / Line 265: @@
 |-
 |8:57
-|<br/> <tt>(1, 2, 3) in x.values()</tt>. True. False
+|(1, 2, 3) in x.values(). True. False
 |-