How to swap values of two variables?

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Daniel Contreras
Daniel Contreras 2017-10-23
评论： lala 2023-8-29
For instance, if i ask the user to input the values of a and b, in this case they choose a=10 and b=5 how would I be able to switch them so that it'll be a=5 and b=10.
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Jan
Jan 2021-10-19
编辑：Jan 2021-10-19
@Subhashini Neelamegam: Yes, but this is more efficient:
function [b, a] = swap(a, b)
end

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采纳的回答

David Goodmanson
David Goodmanson 2017-10-23
Hi Daniel,
Take a look at the 'deal' command, in this case [b a] = deal(a,b)

更多回答（3 个）

Jan
Jan 2017-10-23
Cheaper than deal:
function [b, a] = swap(a, b)
% This function has no body!
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Rik
Rik 2023-8-29
Ran in:
You generally need to warm up function calls if you want to test timings online. This should be reasonably stable. As you can see, they differ by a lot, but in the other direction than your post shows. Using a function instead of a script might also affect the timings (as you can see, the same code runs over 10x faster inside a function).
timeit(@test_deal);timeit(@test_swap);% warm-up round
timeit(@test_deal),timeit(@test_swap)
ans = 0.0798
ans = 0.0017
function test_deal
c1 = zeros(100);
c2 = ones(100);
for i = 1:100000
[c1,c2] = deal(c2,c1);
end
end
function test_swap
c1 = zeros(100);
c2 = ones(100);
for i = 1:100000
[c1,c2] = swap(c2,c1);
end
end
function [a,b] = swap(a,b)
end
lala
lala 2023-8-29
@Rik Thanks for your reply. You are right. :)

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Daniel Afriyie
Daniel Afriyie 2019-10-13
[b, a] = deal(a,b)
AAMIR SHEIKH
AAMIR SHEIKH 2020-8-11
Going Traditionally !!!
a = input("enter a :::");
b = input("enter b :::");
temp = a;
a = b;
b = temp;
[a b]

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