long-integer

问题 I have the following data that i want to convert from wide to long. id_1<-c(1,2,2,2) s02.0<-c(1,1,4,7) s02.1<-c(2,2,5,8) s02.2<-c(NA,3,6,NA) id_2<-c(1,1,2,3) df1<-data.frame(id_1,s02.0,s02.1,s02.2,id_2) I would wish to have the following output based on two unique ids, and added new variable say n, that defines the position of 's02' in each row id_1<-c(1,1,1,2,2,2,2,2,2,2,2,2) id_2<-c(1,1,1,1,1,1,2,2,2,3,3,3) s02<-c(1,2,NA,1,2,3,4,5,6,7,8,NA) n<-c(1,2,3,1,2,3,1,2,3,1,2,3) df2<-data.frame(id_1

问题 I have the following data that i want to convert from wide to long. id_1<-c(1,2,2,2) s02.0<-c(1,1,4,7) s02.1<-c(2,2,5,8) s02.2<-c(NA,3,6,NA) id_2<-c(1,1,2,3) df1<-data.frame(id_1,s02.0,s02.1,s02.2,id_2) I would wish to have the following output based on two unique ids, and added new variable say n, that defines the position of 's02' in each row id_1<-c(1,1,1,2,2,2,2,2,2,2,2,2) id_2<-c(1,1,1,1,1,1,2,2,2,3,3,3) s02<-c(1,2,NA,1,2,3,4,5,6,7,8,NA) n<-c(1,2,3,1,2,3,1,2,3,1,2,3) df2<-data.frame(id_1

问题 Case 1. File: test1.c : unsigned long val = (unsigned long)&"test"; int main() { return 0; } Compiler invocation: cl test1.c /c Results: Microsoft (R) C/C++ Optimizing Compiler Version 19.25.28611 for x64 Copyright (C) Microsoft Corporation. All rights reserved. test1.c test1.c(1): warning C4311: 'type cast': pointer truncation from 'char (*)[5]' to 'unsigned long' test1.c(1): error C2099: initializer is not a constant Case 2. File: test2.c : union { unsigned long val; } val = { (unsigned

问题 Case 1. File: test1.c : unsigned long val = (unsigned long)&"test"; int main() { return 0; } Compiler invocation: cl test1.c /c Results: Microsoft (R) C/C++ Optimizing Compiler Version 19.25.28611 for x64 Copyright (C) Microsoft Corporation. All rights reserved. test1.c test1.c(1): warning C4311: 'type cast': pointer truncation from 'char (*)[5]' to 'unsigned long' test1.c(1): error C2099: initializer is not a constant Case 2. File: test2.c : union { unsigned long val; } val = { (unsigned

问题 Does Java SecureRandom.nextLong() return all possible values given it inherits from Random which uses only 48 bits? If not, can I still do it in Java maybe by modifying the Random class and how to do it? I just want to use an all random long number generator where all possible long values can be returned, if possible. 回答1: While SecureRandom inherits from Random, it doesn't use the same maths or have the same limitation. It will produce all possible 64-bit values eventually. This class

问题 I have a problem to convert a long number to a string in R. How to easily convert a number to string to preserve precision? A have a simple example below. a = -8664354335142704128 toString(a) [1] "-8664354335142704128" b = -8664354335142703762 toString(b) [1] "-8664354335142704128" a == b [1] TRUE I expected toString(a) == toString(b) , but I got different values. I suppose toString() converts the number to float or something like that before converting to string. Thank you for your help.

问题 I have a problem to convert a long number to a string in R. How to easily convert a number to string to preserve precision? A have a simple example below. a = -8664354335142704128 toString(a) [1] "-8664354335142704128" b = -8664354335142703762 toString(b) [1] "-8664354335142704128" a == b [1] TRUE I expected toString(a) == toString(b) , but I got different values. I suppose toString() converts the number to float or something like that before converting to string. Thank you for your help.

问题 Currently, I am using signed values, -2^63 to 2^63-1. Now I need the same range (2 * 2^64), but with positive values only. I found the java documentations mentioning unsigned long, which suits this use. I tried to declare 2^64 to a Long wrapper object, but it still loses the data, in other words, it only captures till the Long.MAX_VALUE , so I am clearly missing something. Is BigInteger the signed long that Java supports? Is there a definition or pointer as to how to declare and use it? 回答1:

问题 Currently, I am using signed values, -2^63 to 2^63-1. Now I need the same range (2 * 2^64), but with positive values only. I found the java documentations mentioning unsigned long, which suits this use. I tried to declare 2^64 to a Long wrapper object, but it still loses the data, in other words, it only captures till the Long.MAX_VALUE , so I am clearly missing something. Is BigInteger the signed long that Java supports? Is there a definition or pointer as to how to declare and use it? 回答1:

问题 I'm trying to sort long numbers in ASC but seems that the comparison is wrong. There is a sequence of correct digits, but from the 7th digit it all messes up. Can anyone advise why? The classes: public class MyTime { private long timeInMicroSeconds; public MyTime (long timeInMicroSeconds) { this.timeInMicroSeconds = timeInMicroSeconds; } } public class tester implements Comparator<MyTime> { public int compare(MyTime o1, MyTime o2) { return (int) ( (-1) * (o2.getTimeInMicroSeconds() - o1