numeric

问题 So I like Haskell, but am dissatisfied with the Num class. So I want to make my own typeclass hierarchic for algebraic types. The problem is, even if I import Prelude hiding Num and everything associated with it, still the only way to make the literal 1 have type t is to make t instance Num. I would love to make my own fromInteger class and leave Num out of the picture entirely, like this import Prelude hiding (everything having to do with Num) import qualified Prelude (everything having to

问题 So I like Haskell, but am dissatisfied with the Num class. So I want to make my own typeclass hierarchic for algebraic types. The problem is, even if I import Prelude hiding Num and everything associated with it, still the only way to make the literal 1 have type t is to make t instance Num. I would love to make my own fromInteger class and leave Num out of the picture entirely, like this import Prelude hiding (everything having to do with Num) import qualified Prelude (everything having to

问题 How do you install blaze natively (i.e., not in a virtual environment) in Python? The only instructions I find are on in the package's doc (see link), and here, in a virtual environment. 回答1: I didn't find any instructions anywhere online for this, but it's relatively straightforward. About my platform/tools I used: Mac OSX (Mountain Lion) Python 2.7.3 homebrew pip It looks like you might need to install Cython, not sure as I already had it installed. You can do this with pip install Cython .

问题 I have a problem when combining the following vectors included in the list: x <- list(as.numeric(c(1,4)),as.numeric(c(3,19,11))) names (x[[1]]) <- c("species.A","species.C") names (x[[2]]) <- c("species.A","species.B","species.C") which gives the following list: >x >[[1]] >species.A species.C > 1 4 >[[2]] >species.A species.B species.C > 3 19 11 combining them using the do.call function: y<- do.call(cbind,x) gives: >y > [,1] [,2] > species.A 1 3 > species.B 4 19 > species.C 1 11 while I would

问题 I'm working in R and have a dataframe, dd_2006, with numeric vectors. When I first imported the data, I needed to remove $'s, decimal points, and some blank spaces from 3 of my variables: SumOfCost, SumOfCases, and SumOfUnits. To do that, I used str_replace_all . However, once I used str_replace_all , the vectors were converted to characters. So I used as.numeric(var) to convert the vectors to numeric, but NAs were introduced, even though when I ran the code below BEFORE I ran the as.numeric

问题 I need to show only the numeric reCaptha instead of character strings. Is it possible? If yes, please give the procedure. Like Google's Street view 回答1: It is not possible at the moment. Your only options for customisation are basically just skins/themes. If such an option were available, it would also not be in the options passed through on the client side as a bot could just request it as an easier alternative. Even the plugins only generate javascript to display the widget. So the option

问题 Is it possible for a pattern match to detect if something is a Numeric ? I want to do the following: class DoubleWrapper(value: Double) { override def equals(o: Any): Boolean = o match { case o: Numeric => value == o.toDouble case _ => false } override def hashCode(): Int = value ## } But of course this doesn't really work because Numeric isn't the supertype of things like Int and Double , it's a typeclass. I also can't do something like def equals[N: Numeric](o: N) because o has to be Any to

问题 I have a set of data like a b 0 type 1 True 1 type 2 False How can I keep the numerical part of column a and transfer ture to 1, false to zero at the same time. Below is what I want. a b 0 1 1 1 2 0 回答1: You can convert Booleans to integers as follows: df['b'] = df.b.astype(int) Depending on the nature of your text in Column A , you can do a few things: a) Split on the space and take the second part (either string or int depending on your needs). df['a'] = df.a.str.split().str[1] # Optional `

问题 Suppose I have a data.frame that's completely numeric . If I make one entry of the first column a character (for example), then the entire first column will become character . Question : How do I reverse this. That is, how do I make it such that any character objects inside the data.frame that are "obviously" numeric objects are forced to be numeric ? MWE: test <- data.frame(matrix(rnorm(50),10)) is(test[3,1]) test[1,1] <- "TEST" is(test[3,1]) print(test) So my goal here would be to go FROM

问题 This question already has answers here : Are all integer values perfectly represented as doubles? [duplicate] (5 answers) Closed last year . Are there any 64-bit unsigned integer values which cannot be represented with a double-precision floating-point type? (As a double is also 64-bit wide there must be some.) If so, how can I calculate all of them? (In a not brute force way, maybe?) 回答1: Every integer from 0 to 2^52 inclusive is representable exactly, from 2^52 to 2^53 only every even