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Python Python Collections (Retired) Tuples Tuple Packing And Unpacking

Bill Talkington
Bill Talkington
11,840 Points
Posted by Bill Talkington
Bill Talkington
11,840 Points

b = a?

At 3:28, you say copy 'c' to 'b', but the video shows 'a' being copied to 'b' after is has been updated to equal 2.

Did I catch that right?

1 Answer

Robert Richey
PLUS
Robert Richey
Courses Plus Student 16,352 Points
Robert Richey
Robert Richey
Courses Plus Student 16,352 Points

Hi Bill,

Kenneth is just using an example for how other programming languages swap the value of variables - by having to create a temporary third variable. Here, I'm calling the temporary variable tmp instead of c just to more easily illustrate the idea.

# just an example, don't actually do this in python

# the setup
a = 1
b = 2

# the swap
tmp = a  # tmp == 1
a = b  # a == 2
b = tmp  # b == 1

# the finale
a = 2
b = 1

# instead, do this
a, b = b, a
Bill Talkington
Bill Talkington
11,840 Points
Bill Talkington
Bill Talkington
11,840 Points

Thanks for the reply.

I understand what he was explaining. However, what is shown and what is said in the video could come off as incongruent to a beginner.

The temporary variable in the video (c) is never visually copied to b in code form (the arrow implicitly does).

The end result that is shown is correct, I was just worried about a beginner trying to execute exactly what is shown on the screen. Maybe I'm just being too picky! ;)

Robert Richey
Robert Richey
Courses Plus Student 16,352 Points

Ah, yes, I see what you mean. I agree, the pseudo-code was a bit confusing to me also, but since I already understood variable swapping I really didn't think much about it.