Q$3$: WWPD: Lambda

Use Ok to test your knowledge with the following "What Would Python Display?" questions:

python$3$ ok $-$q lambda $-$u$$

As a reminder, the following two lines of code will not display any output in the interactive Python interpreter when executed:

$>>>$ x $=$ None

$>>>$ x

$>>>$

$>>>$ lambda x: x # A lambda expression with one parameter x

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$>>>$ a $=$ lambda x: x # Assigning the lambda function to the name a

$>>>$ a$(5)$

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$>>>($lambda: $3)()$ # Using a lambda expression as an operator in a call exp.

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$>>>$ b $=$ lambda x$,$ y: lambda: x $+$ y # Lambdas can return other lambdas!

$>>>$ c $=$ b$(8,4)$

$>>>$ c

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$>>>$ c$()$

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$>>>$ d $=$ lambda f: f$(4)$ # They can have functions as arguments as well.

$>>>$ def square$($x$)$:

$...$ return x $*$ x

$>>>$ d$($square$)$

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$>>>$ higher$\_$order$\_$lambda $=$ lambda f: lambda x: f$($x$)$

$>>>$ g $=$ lambda x: x $*$ x

$>>>$ higher$\_$order$\_$lambda$(2)($g$)$ # Which argument belongs to which function call?

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$>>>$ higher$\_$order$\_$lambda$($g$)(2)$

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$>>>$ call$\_$thrice $=$ lambda f: lambda x: f$($f$($f$($x$)))$

$>>>$ call$\_$thrice$($lambda y: y $+1)(0)$

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$>>>$ print$\_$lambda $=$ lambda z: print$($z$)$ # When is the return expression of a lambda expression executed?

$>>>$ print$\_$lambda

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$>>>$ one$\_$thousand $=$ print$\_$lambda$(1000)$

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$>>>$ one$\_$thousand # What did the call to print$\_$lambda return?

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