how can i compute the length of an integer?

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Zaza
Zaza 2013-1-4
评论： Christian Ziegler 2020-11-14
if i have
int = 12345;
length_int = 5;
???

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采纳的回答

Azzi Abdelmalek
Azzi Abdelmalek 2013-1-4
编辑：Azzi Abdelmalek 2013-1-4
int=-123456789
max(ceil(log10(abs(int))),1)
  1 个评论
Christian Ziegler
Christian Ziegler 2020-11-14
this doesn't work for 10, 100, 1000...
for example max(ceil(log10(abs(10))),1) equals 1 but it should be 2
simple fix:
int = 10;
max(ceil(log10(abs(int)+1)),1)

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更多回答（2 个）

Sean de Wolski
Sean de Wolski 2013-1-4
编辑：Sean de Wolski 2013-1-4
Edit
nnz(num2str(int) - '-')
  4 个评论
显示 2更早的评论
Friedrich
Friedrich 2013-1-4
Good point Sean. But then
numel(num2str(abs(int)))
should do ;)

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Davide Ferraro
Davide Ferraro 2013-1-4
Casting the variable into a string may be risky because you may get to "unexpected" cases such as:
int = 12345678901234567890123
numel(num2str(int))
ans =
12
You may consider a numeric approach using LOG10: floor(log10(int))+1 all numbers between 10 and 100 will have a LOG10 between 1 and 2 so you can use FLOOR to get the lower value (1 in this case) and then you need to add the value 1 cause you are trying to compute the number of digits and not the power of ten.
  1 个评论
G A
G A 2013-1-4
编辑：G A 2013-1-4
why, it works:
>> int = 12345678901234567890123
numel(num2str(int))
int =
1.2346e+22
ans =
23

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