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Welcome back. One more thing to note about dictionaries is aliasing.

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So, on line one,

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we create a dictionary that has three key value pairs.

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On line two, we assign a new variable called alias to be that dictionary.

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On line four, we print out is alias opposites.

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This is asking, are they pointing to the same object?

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So, if we run CodeLens on lines one through four,

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then we'll see again line one creates a dictionary and

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line two assigned alias to point to the exact same object of that dictionary.

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Now, this is important because here,

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if we say alias sub right equals left,

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we're assigning right from its previous value which was wrong,

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and then we print out opposites sub right,

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then we're actually going to print out left on line seven.

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So, here, we can see line four says true because alias is the same object as opposites.

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But now, when we print out opposites sub right,

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we now get left.

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That's despite the fact that we first assigned opposite sub right to be wrong,

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and in all of these lines,

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we never directly changed opposites sub right.

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But the culprit here is that on line six,

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when we changed alias sub right to be left,

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then that also have changed opposite sub right.

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Again, we can use CodeLens to see why that is.

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So, on line one,

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we create a dictionary and then we assign alias to be that exact same dictionary.

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We can see alias is opposites.

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Now, when we assign alias sub right to now be left,

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then that modifies that dictionary.

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So, if that right is now left and that change

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the value associated with the key right to be left for both opposites and alias.

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So, let's go through a question related to this.

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So, here, on the first line,

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we create a dictionary with

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four key value pairs and then we assign yourdict to be my dictionary.

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So, yourdict is pointing to the same dictionary.

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Then, we say yourdict sub elephant equals 999.

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Now, remember, yourdict and mydict are the same object here.

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So, when we assign it elephant to be 999,

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that erases the value 23 and replaces it with

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999 for both of these dictionaries because they're pointing at the same object.

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So, now, when we print out mydictionary sub elephant,

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then we're going to get the value 999.

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That's all for now, until next time.