edit: this question has been marked as a duplicate. I did indeed look through all the previous similar questions I could find and haven’t found an answer. Basically, I am not able to control how the program compiles (though I think it’s already using c++11), so I’m either looking for a reason why stoi isn’t … Read more
I’m going to attempt to explain this without making any mistakes, but I’m betting this will attract a clarification or two in the comments. A data frame is a list. When you subset a data frame using the name of a column and [, what you’re getting is a sublist (or a sub data frame). If you want … Read more
You could simply do : Or you could get double from Long object as :
You should instead use std::strtoul, found in <cstdlib>, which is designed for unsigned numbers, has a larger range, and reports errors better. If you want to use std::string for input and exceptions for error handling, use std::stoul. A short, highly efficient implementation would be as follows: This will be much faster than istringstream, culture-invariant (so no unexpected changes to behavior when … Read more
What you are looking for is ‘type casting’. typecasting (putting the type you know you want in brackets) tells the compiler you know what you are doing and are cool with it. The old way that is inherited from C is as follows. If you had only tried to write You would have got a warning that … Read more
From the .NET reference source: So, your answer is that they are exactly the same, under the hood. Any preference between the two is strictly a personal style choice. Personally, I would always use the cast as it is shorter and and just seems more idiomatic to me.
It turns out I was just missing DECIMAL on the CAST() description: DECIMAL[(M[,D])] Converts a value to DECIMAL data type. The optional arguments M and D specify the precision (M specifies the total number of digits) and the scale (D specifies the number of digits after the decimal point) of the decimal value. The default … Read more
I expect the output should be 4.08000000 whereas I got only 4.00000000. Is there any way to get the numbers after the dot?
Your array is of byte primitives, but you’re trying to call a method on them. You don’t need to do anything explicit to convert a byte to an int, just: …since it’s not a downcast. Note that the default behavior of byte-to-int conversion is to preserve the sign of the value (remember byte is a … Read more
If you explicitly cast double to int, the decimal part will be truncated. For example: Moreover, you may also use Math.floor() method to round values in case you want double value in return.