How to generate one random integer

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Roxanne Esguerra
Roxanne Esguerra 2020-7-3
评论： Dyuman Joshi 2024-1-28
I need to generate one random integer.
I tried these codes:
X = randi(1)
X = rand(1)
However, it only gives random numbers between 0 and 1 (like 0.2567, 0.9432, etc.).
I am hoping to get a random number from negative infinity to positive infinity.
What function should I use to be able to generate one random integer?
Thanks in advance!
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David
David 2024-1-28
Right, I agree that isinteger is testing that a value is a member of the "integer class", but if randi purports to produce pseudo-random integers, then shouldn't results me members of the interger class without explaicitly declaring that they are; i.e., without the need for the "int16" declaration. (I guess not, and I appreciate your response, but if a function says it is returning an integer, then in my book, it should actually return an integer that tests "true" for being a member of that class. That's why I think this is confusing.
Dyuman Joshi
Dyuman Joshi 2024-1-28
There's a difference between the integer as a data type and integer as a numerical entity.
The function randi() does return an integer, but, by default, it is of class double.

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KSSV
KSSV 2020-7-3
编辑：KSSV 2020-7-3
As you cannot fix infinity, decide a huge/large number ..say 10^5 and use:
x = randi([-10^5 10^5],1)

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Walter Roberson
Walter Roberson 2020-7-3
编辑：Walter Roberson 2024-1-28
The following generates integers natively.
typecast(randi([0 255],1,8,'uint8'),'int64')
The range is all possible integers between -2^63 and +2^63-1
infinity cannot be generated with this setup, as infinity is not part of the integer system.
To generate integers outside of the range indicated above, you need to switch to double(), but if you do that, you only have 53 bits of precision available, and all values outside the range +/- 2^53 are integers that are multiplied by a power of 2 -- you could not, for example, generate 2^53 + 17 . By 1E50, adjacent representable values are 2^114 apart. Is that what you want to deal with?

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