Integer check

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Andy 2011 年 9 月 21 日
コメント済み: Phani 2021 年 10 月 6 日
How can i do an integer check in matlab? Say i have a number, a = 1.5, how do i check if it is integer or not? i want to use an if statement:
if non_integer(a) == true
so i need to know what to use for "non_integer", which would return a true or false
  1 件のコメント
Phani 2021 年 10 月 6 日
I think you can use rem function which throws out the remainder.
if(rem(a,1) ~=0) %checks if a is an integer with help of remainder



Sean de Wolski
Sean de Wolski 2011 年 9 月 21 日
  3 件のコメント
Thorsten 2016 年 11 月 2 日
Like it should not. Because Inf is not an integer, but
floor(inf) == inf
returns true.
So the correct test would be
~isinf(x) & floor(x) == x
Or, as Walter suggests,
mod(x,1) == 0
But this may be all just of theoretical interest.


その他の回答 (4 件)

Walter Roberson
Walter Roberson 2011 年 9 月 21 日
I suggest you think about floor(), ceil(), fix(), and round()
  2 件のコメント
Walter Roberson
Walter Roberson 2016 年 11 月 2 日
NaN == 0 is false, so in each of those cases, the result of the test would be false, indicating that the values are not integers.
But if you tried the one above, floor(inf)==inf then the result would be true, seemingly indicating that it is an integer when it is not.


Fandi Bataineh
Fandi Bataineh 2019 年 2 月 2 日
編集済み: Fandi Bataineh 2019 年 2 月 2 日
this will be true only for integers
  1 件のコメント
Sivyer Ge
Sivyer Ge 2019 年 2 月 24 日
Actually this will not work for type 'char'. Do you know other way to identify the difference between char and integer?


Manuel Alcazar
Manuel Alcazar 2019 年 9 月 16 日
function [bool,idx] = isint(x)
% Check whether input is integer or not
% Inf and NaN are not integers
if ~isnumeric(x)
error('Input must be a numeric, not a %s.',class(x))
bool = (mod(x,1) == 0);
% bool = (round(x) == floor(x)); % Other approach. Fails with Inf and
% NaN.
idx = find(bool);
% Manolín Sept-2019

per isakson
per isakson 2019 年 9 月 16 日
function isf = isflint( m )
% floating double only
% JanSimon: ...
% command-confusion#answer_78914
assert( isa( m, 'double' ) && isvector( m ) ...
, 'isflint:IllegalInput' ...
, 'The input should be a double vector' )
isf = all( abs( m ) <= flintmax ) ...
&& all( floor( m ) == m ) ;
  1 件のコメント
Stephen23 2019 年 9 月 16 日
This could be trivially vectorized: why force it to return a scalar?



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