nan

问题 This question already has an answer here : R: How can I extract an element from a column of data in spark connection (sparklyr) in pipe (1 answer) Closed last year . I began to use sparklyr to handle big size data, so I need to use only pipe lines. But while manupulating data frame I got in trouble and it seems by csj %>% head() below is how my data looks like. enter image description here What I want to do is first, I want to make a new column, lenght_of_review, with counting number of

问题 I am trying to calculate the zscore for a vector of 5000 rows which has many nan values. I have to calculate this many times so I dont want to use a loop, I was hoping to find a vectorized solution. the loop solution: for i = 1:end vec(i,1) = (val(i,1) - nanmean(:,1))/nanstd(:,1) end a partial vectorized solution: zscore(vec(find(isnan(vec(1:end) == 0)))) but this returns a vector the length of the original vector minus the nan values. Thus it isn't the same as the original size. I want to

问题 I use boost serialization in my C++ / CLI program, and some classes have datamembers that contain some double which are initialized to arma::datum::nan (the "not-a-number" value for armadillo library). I serialize via a boost::archive::text_oarchive. When I try to deserialize via boost::archive::text_iarchive oa, a boost serialization archive exception is launched when it tries to read a arma::datum::nan value. I tried using a binary archive, but it seems other types (std::vector> for

问题 When I do this: var x = parseInt("–2147483648"); console.log(x); I get the value as: NaN Why does this happen? I want to test if a number is in the range of C (int), so I am doing the above, but it does not work. Also, I want to do this for C (long), is there a way to this? For example: If I do: var x = parseInt("-9223372036854775808"); console.log(x); Now, I know that (-+)2^53 is the limit of numbers in Javascript. Is there some other way to test if the given value in a form is actually in

问题 I write code in LINUX RHEL 64bit, and use C++98. I have an array of floating point values, and I wanted to 'mark' some values to be 'invalid'. One possible solution is to use another bit-array to tell if the corresponding value is valid. I was wondering if we can use any special double value. The link Why does IEEE 754 reserve so many NaN values? says that there are lot of NaN values. Can we use any value reserved for my problem? I only need one bit in the payload to indicate if a double

问题 I want to calculation the rms with the Intel sse intrinsic. Like this: float rms( float *a, float *b , int l) { int n=0; float r=0.0; for(int i=0;i<l;i++) { if(finitef(a[i]) && finitef(b[i])) { n++; tmp = a[i] - b[i]; r += tmp*tmp; } } r /= n; return r; } But how to check which elements are NaN? And how to count n? 回答1: You can test a value for NaN by comparing the value with itself. x == x will return false if x is a NaN. So for a SSE vector of 4 x float values, vx: vmask = _mm_cmpeq_ps(vx,

问题 I recently read this about NaN values in SSE arithmetic operations: The result of arithmetic operations acting on two not a number (NAN) arguments is undefined. Therefore, floating-point operations using NAN arguments will not match the expected behavior of the corresponding assembly instructions. Source: http://msdn.microsoft.com/en-us/library/x5c07e2a(v=vs.100).aspx Does this mean that, say, adding two __m128 values might convert a NaN to a real? If a calculation relied on a NaN value, I

问题 I'm totally new to python. I've used some code found online and I tried to work on it. So I'm creating a text-document-matrix and I want to add some extra features before training a logistic regression model. Although I've checked my data with R and I get no error, when I run the logistic regression I get the error "ValueError: Array contains NaN or infinity." I'm not getting the same error when I do not add my own features. My features are in the file "toPython.txt". Mind the two calls to

问题 I have a data frame containing NaN's that I'd like to convert to 0's. I wrote a function that I think should work: fix_nan <- function(x){ return(x[is.nan(x)] <- 0) } And then I apply it to the data frame: train_e <- structure(list(pack_id = structure(1:10, .Label = c("1", "2", "4", "5", "7", "8", "9", "10", "11", "14"), class = "factor"), item_1 = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0), item_2 = c(NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN), item_3 = c(1.45225232891169, 0.613104472886409, NaN

问题 I've written a function for calculating the standard deviation and the result is always '1.#QNAN0', I've tried formatting it in different ways but I can't find a solution. It was working on a different computer yesterday, is there anything I can do? void CalcStandardDeviation(int count, int* nums, double mean, FILE* output){ int k; double std=0,a; for (k=0; k<count; k++){ a=nums[k]-mean; std=std+(a*a); } std/=(count); std=sqrt(std); fprintf(output,"Standard deviation: %f\r\n",std); fprintf