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# how can i compute the length of an integer?

Asked by Zaza on 4 Jan 2013

if i have

int = 12345;

length_int = 5;

???

## 1 Comment

Jan Simon on 4 Jan 2013

What is the "length" of -1 and 0?

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Answer by Azzi Abdelmalek on 4 Jan 2013
Edited by Azzi Abdelmalek on 4 Jan 2013
```int=-123456789
max(ceil(log10(abs(int))),1)
```

Answer by Sean de Wolski on 4 Jan 2013
Edited by Sean de Wolski on 4 Jan 2013

Edit

```nnz(num2str(int) - '-')
```

Sean de Wolski on 4 Jan 2013

Friedrich, neither work actually, consider -12345.

Friedrich on 4 Jan 2013

Good point Sean. But then

```numel(num2str(abs(int)))
```

should do ;)

Sean de Wolski on 4 Jan 2013

arghh, you win!

Answer by Davide Ferraro on 4 Jan 2013

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 Comment

G A on 4 Jan 2013

why, it works:

` >> int = 12345678901234567890123`
`    numel(num2str(int))`
```int =
```
`   1.2346e+22`
```ans =
```
`    23`