Integer conversion without precision loss for literal function inputs
显示 更早的评论
The function uint64 can take a literal input that is not representable by double and convert without precision loss, like
uint64(7725400999518902274)
Unfortunately, this functionality does not seem to extend to a function with an argument block and type validation.
function test(a)
arguments
a (1,1) uint64
end
disp(a)
end
test(7725400999518902274)
I would have to do
test(uint64(7725400999518902274))
Does anyone know if there is a trick to get this functionality or I am otherwise missing something?
4 个评论
uint64(double(7725400999518902274))
uint64(7725400999518902274)
Unfortunately, this functionality does not seem to extend to a function with an argument block and type validation.
The argument block isn't the issue. Here's the same problem without it:
test(7725400999518902274)
function test(a)
a=uint64(a);
disp(a)
end
"The function uint64 can take a literal input that is not representable by double and convert without precision loss"
That is not true, it can do that within [0, 2^64-1]
uint64(123456789012345678901)
uint64(2^64-1)
uint64(2^64+1)
AB
2025-11-20
采纳的回答
test 7725400999518902274
function test(a)
arguments
a (1,:) string
end
a=eval("uint64("+ a + ")"),
end
8 个评论
Matt - You are providing a string as an input, however OP is providing a double value.
The same problem resurfaces when providing the input as double -
test(7725400999518902274)
function test(a)
arguments
a (1,:) string
end
a=eval("uint64("+ a + ")"),
end
No, the OP is providing the number as a literal. The Matlab parser clearly does not interpret literal input to uint64 as a double, since,
A=uint64(7725400999518902274);
B=uint64(double(7725400999518902274));
isequal(A,B)
AB
2025-11-20
Dyuman Joshi
2025-11-20
@Matt J - Yes, you are right. That was an oversight by me.
Dyuman Joshi
2025-11-20
@AB, using sscanf is what is suggested in the documentation as well - https://in.mathworks.com/help/matlab/ref/uint64.html#mw_73911831-6f61-4aae-89d5-5afb9ff9a902.
I wondered whether uint64() of a string object could work, but unfortunately it does not.
ABC="7725400999518902274"
double(ABC)
uint64(ABC)
Is there any reason to prefer command syntax? Function syntax seems to work fine.
test 7725400999518902274
test("7725400999518902274")
function test(a)
arguments
a (1,:) string
end
a=eval("uint64("+ a + ")"),
end
更多回答（1 个）
Walter Roberson
2025-11-21
2 个投票
Does anyone know if there is a trick to get this functionality
There is no way of doing that.
Any way of doing that would have to affect the inputs at parse time. However, arguement blocks do not affect parse time. Arguement blocks apply conversions to whatever input was passed in. By the time the arguement block processing is applied, the parameter has already been parsed as double precision.
类别
在 帮助中心 和 File Exchange 中查找有关 Characters and Strings 的更多信息
Translated by 
