WEBVTT
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In the last lesson, we added an external library to our project.
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Now it's time to construct a prettytable object and practice using its methods
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and attributes. Our starting point as always
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is the documentation. Here
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you can see how to construct an actual prettytable object.
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So let's use what we've learned previously about constructing objects to go
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ahead and create this object from the class. Now, firstly,
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we're going to do the same thing as we did previously with turtle.
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We're going to tap into the package prettytable,
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and then we're going to import the prettytable class noted by the c here.
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Now that we have access to this class inside our code,
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I want you to go ahead and create an object from this pretty table class and the
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object should be named table. So pause the video and give that a go.
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All right. So we said I'll object is going to be called table,
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and then we're going to construct it from this class called a prettytable.
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So we're going to put it in with its casing.
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So this is the Pascal case that we spoke about earlier on,
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and then in order to actually give it the go-ahead and construct,
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we have to add the parentheses at the end.
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So now you've created a new object called table from this prettytable and we
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can actually go ahead and print this table. And even at this stage,
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it's ready going to start printing out a bare bones version all the table.
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But of course this table has no datas
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So it's actually kind of hard to visualize what all of these ASCII characters
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are doing in an empty table.
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But no matter, the next thing we can see in our documentation is how to go about
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adding columns. So it's got this method, remember methods
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are functions that are associated with an object and this method will add columns to
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whatever table we specify. Now the method takes two inputs.
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One is the name of the field,
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so our field names are Pokemon name and type.
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And then we've got a list of strings
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which is going to be the data that's going to go into that column. Essentially,
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every time we call that method, add column,
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it's going to allow us to give a field name as a string,
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and then a list of data in order that they're going to go into the table.
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So we're going to add our table one column at a time. Using that documentation
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see if you can add both of these columns to our table object and then once
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you've done that, we're going to print the table object again
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and we should be to see an ASCII table. This is what you're aiming for
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when you run your code.
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It should print out your table and nicely format it in this ASCII style.
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Pause the video and complete the challenge.
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Right?
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All right.
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So we've got our table object and remember that methods are functions that are
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associated with the object. So we say table object dot,
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and then we get to call that method,
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add_column. And notice how it takes two inputs,
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the field name and the data that's going to go into the column.
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So the field name is going to be a string,
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and this is going to be the name at the top of our column. So in our case,
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it was called Pokemon name. And then after a comma,
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we get to put in a list of all the data that's going to go into our column.
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So just as a quick reminder, our first column contains Pikachu,
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Squirtle and Charmander.
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Now, we should have added a column to our table and you can safely ignore all
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of these typos because of course, Pokemon names are not real words.
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But if you wanted to check against the poke dex
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you can actually go to this link in the course resources,
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and you can see how each of these Pokemon are spelt. Now,
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the next thing we want to add is the associated type with each of these
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Pokemons. So for example, Charmander is a fire type of Pokemon,
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Squirtle is a water type Pokemon,
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but essentially we're going to add the data that's in the second column.
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So the field name is called type, and then we've got three pieces of data
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that's going to need to go into the list in the same order as the previous
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Pokemon. That way we'll actually match them up properly.
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So if you haven't already, go ahead and add the second column.
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Right?
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So again,
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I'm going to call the same method on my table and this time I'm going to add the
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field type and the data is going to go in the order of the data that I had from
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the previous column. So the first one is the type of Pikachu which is electric.
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And the second one is the type for Squirtle, which is Water. And finally,
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we've got fire for Charmander.
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So now this will be matched to this,
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this will be matched this and so on and so forth.
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If we go ahead and print our table now, so
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if we run our code and take a look in here,
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you can see how we've now got a nicely formatted table by creating an object
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from this pre-made prettytable class and we've now called this method
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add_column to add two columns. And when we print our table,
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it's now nicely formatted in ASCII. Now,
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remember that we can also change the object's attributes.
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For example, if we wanted to change the appearance of our table,
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that's probably controlled by an attribute. If you scroll down,
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you can see that we can change the table style by tapping into each of these attributes.
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For example, if I wanted to change the alignment of my data in the table,
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I can change this align attribute to L for left-align, C for the center-align or
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R for right-aligned.
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Do you remember how to tap into an object's attribute? If you do,
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go ahead and see if you can change our table from center-aligned by default to
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left-aligned. Pause the video and try to complete that challenge.
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Right?
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So again,
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we're going to tap into our table object and we're going to use the dot
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notation, but this time
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instead of accessing a method associated with the object
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which is of course denoted by the M, we're going to access an attribute or in
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this case, they've titled F which is a field.
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And the one that we want is this align. So let's go ahead and type align,
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and now we have access to this attribute. Let's see what happens
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if I go ahead and print this align attribute.
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You can see that for both of my columns, Pokemon name and type,
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the align attribute is set to C, which is centered.
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What I want to do is change the whole table to be left-aligned. Just as we would
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with any other variable we can of course print it,
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but we can also change it.
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And we would change a variable by just using the equal sign, right?
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So let's change the alignment to left-aligned,
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and now let's run the code again.
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And you can see now both of my columns are now aligning with the left hand
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margin.
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So we've seen how we can use attributes
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like the ones here to change the styling of our table.
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We've seen how we can use methods
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like add_column or add_row to work with this table object and get it to
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perform some sort of functionality, like adding pieces of data to it.
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And we've seen how we can create new objects by simply constructing it from the
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blueprint class. Feel free to mess around with prettytable
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as much as you like change, other things about it,
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or add different pieces of data.
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But once you're happy with creating the object changing the attributes and
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calling the methods,
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then head over to the next lesson where I've got a quiz for you.