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Hello and welcome to this tutorial on python dictionary.

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A dictionary consists of a collection of key value pets and each key value pair.

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Maps key toward associated revenue.

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So here I have defined keys such as name age class height and weight.

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And these are the values the keys and the values are separated by coolant.

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So age is 5.

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Class is Grade 1.

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Height is 3 feet and weight is 20 kilos.

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And a dictionary can be defined by enclosing comma separated key while you pairs in curly braces.

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So here we have a dictionary dict to 1 which maps the keys to the values you are given key can appear

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in a dictionary only once so duplicate keys are not allowed in a dictionary and an empty dictionary

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is represented with a pair of curly braces.

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Make this next.

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Dictionaries are mutable and are un ordered collections of data.

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You can add items or delete items from a dictionary without creating new copies so a dictionary can

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be changed in place.

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We have talked about lives before.

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Lists are an ordered collection of data.

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That means they retain the order of the items in which we insert it.

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If we want to access or retrieve the elements in the list they are accessed using index numbers coming

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to a dictionary.

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A dictionary is in an ordered collection of data.

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That means when you add or delete entries from a dictionary you won't be guaranteed that any sort of

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order will be maintained.

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And if you want to retrieve all value from a dictionary we can retrieve the value using Dickey.

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Say for example a one that is aisle one 2 and 3.

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I'll forward Dickies in the dictionary and if we want to retrieve any of these values we can retrieve

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using the keys.

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So the mapping of the values with Dickies remains fixed but not deep position.

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It might vary.

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So when we want to access elements in a dictionary we do not access elements based on the position we

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do it based on these guys.

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Next a dictionary key must be of the type immutable that means we can use an integer offload a string

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or a boolean as a dictionary key coming to the dictionary value it can be of any type.

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So it could include lists and other dictionaries as well and dictionaries like lists support nesting

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to any debt addiction any key in appear in a dictionary.

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Only once and a dictionary can be created with the burden dict function.

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So this is the python built in function and to this function we need to parse arguments which are a

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sequence of key value pairs say for example in these key value pairs have to be included in a list.

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Say for example I have the key value PID H.

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Tom next I have class as the key Grade 1 is devalued.

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This is another key value pair.

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And this is parsed in a list to the dict function.

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So let's check this in the Jupiter notebook.

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So here define a dictionary dict one with the key value pairs separated by comma and then finally enclosed

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in curly places.

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So this is how we can define a dictionary.

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Select let's display this dictionary dict.

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1.

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Let us also see how we can define a dictionary using the dict function.

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So we will define and not the dictionary dict to using this dict.

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Function so right now since we have not included any key value pairs this is going to be an empty dictionary.

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Now we will add a few key value pairs to the dictionary to do so.

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Here I have created the dictionary dict to using the dict function and I have passed a list of key value

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pairs as argument to the dict function so let's execute this and display the dictionary to do so.

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Here is the dictionary to do displayed a value is retrieved from a dictionary by specifying its corresponding

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key in square brackets.

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So we have a dictionary dict to one year and say for example we want to know the items that are stored

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in a one I won.

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So in order to retrieve the value in the key a one we need to parse the key in square brackets like

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this and then execute.

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So you have your value retrieve for the corresponding key so similarly you can retrieve other keys using

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the square brackets.

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Say for example you want to add a key value pair to an existing dictionary.

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Say for example this is the dictionary dict 1 and you want to add another aisle to the existing dictionary

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so you have a 5 and you want to assign the value data in a 5 so let's now display the dictionary dict

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1.

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So here we have the dictionary dict 1.

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The dictionary Key needs to be an immutable later type.

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Dictionary value can be of any type.

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So let us now create another dictionary which contained a list of elements as devalue so he could have

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defined another dictionary dict 3 which has only one key country and then the value is a list of elements.

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India China and Brazil.

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In order to access the value in this dictionary we need to give the dictionary dict 3 and in square

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brackets pass the key and the key is country.

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And for example if you want to retrieve any of these elements in the list we need to add an additional

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index to this or dict 3.

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The first index contains the key country and within this key we want to the dream.

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The second element that is China.

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So the index for this element in this particular list is 1.

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So this is how you retrieve the elements in a sublease.

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Another example that a dictionary has another dictionary defined in it.

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So here we have the dictionary dict Ford which has one key type and the value is another dictionary

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which is enclosed in curly braces here.

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So in order to access the value which is assigned to type which is key parse the key in these square

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brackets and here you have the dictionary.

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Now in order to access these sub dictionary add an additional index and here you parse parse the key

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immutable which is defined in the sub dictionary.

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Now when you execute this you have the value that is assigned to the key immutable.