numbers

I need to find a way to convert a large number into a hex string in javascript. Straight off the bat, I tried myBigNumber.toString(16) but if myBigNumber has a very large value (eg 1298925419114529174706173) then myBigNumber.toString(16) will return an erroneous result, which is just brilliant. I tried writing by own function as follows: function (integer) { var result = ''; while (integer) { result = (integer % 16).toString(16) + result; integer = Math.floor(integer / 16); } } However, large numbers modulo 16 all return 0 (I think this fundamental issue is what is causing the problem with

Possible Duplicate: Replace contents of factor column in R dataframe I have the data.frame df1<-data.frame("Sp1"=1:6,"Sp2"=7:12,"Sp3"=13:18) rownames(df1)=c("A","B","C","D","E","F") df1 Sp1 Sp2 Sp3 A 1 7 13 B 2 8 14 C 3 9 15 D 4 10 16 E 5 11 17 F 6 12 18 I want to replace every entry of the number 8 in the column df1$Sp2 with the number 800. I have tried: test<-replace(df1$Sp2,df1[800,"Sp2"],5) e.g.: df1$Sp2[df1$Sp2 == 8] <- 800 来源： https://stackoverflow.com/questions/11817371/replace-numbers-in-data-frame-column-in-r

Well, there are at least two low-level ways of determining whether a given number is even or not: 1. if (num%2 == 0) { /* even */ } 2. if ((num&1) == 0) { /* even */ } I consider the second option to be far more elegant and meaningful, and that's the one I usually use. But it is not only a matter of taste; The actual performance may vary: usually the bitwise operations (such as the logial-and here) are far more efficient than a mod (or div) operation. Of course, you may argue that some compilers will be able to optimize it anyway, and I agree...but some won't. Another point is that the second

How do i convert a oracle varchar value to number eg table - exception exception_value 555 where exception_value is a varchar type I would like to test the value of exception_value column select * from exception where exception_value = 105 instead of select * from exception where exception_value = '105' You have to use the TO_NUMBER function: select * from exception where exception_value = to_number('105') Since the column is of type VARCHAR, you should convert the input parameter to a string rather than converting the column value to a number: select * from exception where exception_value =

I do my php work on my dev box at home, where I've got a rudimentary LAMP setup. When I look at my website on my home box, any numbers I echo are automatically truncated to the least required precision. Eg 2 is echoed as 2, 2.2000 is echoed as 2.2. On the production box, all the numbers are echoed with at least one unnecessary zero, eg 100 becomes 100.0. On both boxes, the PHP version is 5.2.5. Does anyone know offhand if there is a setting I can change which will force PHP to automatically remove any unnecessary zeroes? I don't want to have to go to every place in my code where I output a

i want to get some string, range from 0000 to 9999, that's to say, i want to print the following string: 0000 0001 0002 0003 0004 0005 0006 .... 9999 i tried to use print "\n".join([str(num) for num in range(0, 9999)]) , but failed, i get the following number: 0 1 2 3 4 5 6 ... 9999 i want python to add the prefix 0 automatically, making the number remain 4 bit digits all the time. can anyone give a hand to me? any help appreciated. One way to get what you want is to use string formatting: >>> for i in range(10): ... '{0:04}'.format(i) ... '0000' '0001' '0002' '0003' '0004' '0005' '0006' '0007