array

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have an array of doubles, and I want to create a 4-by-4 matrix using the Eigen library. I also want to specify that the data is stored in row-major order. How can I do this? I have tried the following, but it does not compile: double data[16]; Eigen::Matrix4d M = Eigen::Map<Eigen::Matrix4d>(data, 4, 4, Eigen::RowMajor); 回答1: You need to pass a row-major matrix type to Map, e.g.: Map<Matrix<double,4,4,RowMajor> > M(data); then you can use M as an Eigen matrix, and the values of data will be modified, e.g.: M = M.inverse(); If you want to

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I did research on this, and wasn't able to find an exact answer. Most of the questions/answers on here pertaining to this seem to be unfinished. If anyone knows of a finished solution similar to my question, please point me in that direction! Here is my array: Array ( ['home'] => Array ( [0] => sub-home1 [1] => sub-home2 ) ['about'] => Array ( [0] => sub-about ['about2'] => Array ( [0] => sub-sub-about ) ) ['staff'] => Array ( [0] => sub-staff1 [1] => sub-staff2 ) ['contact'] => contact ) And here is what I would like to turn it into: <ul>

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I have an image converted to a ndarray with RGBA values. Suppose it's 50 x 50 x 4. I want to replace all the pixels with values array([255, 255, 255, 255]) for array([0, 0, 0, 0]) . So: from numpy import * from PIL import Image def test ( mask ): mask = array ( mask ) find = array ([ 255 , 255 , 255 , 255 ]) replace = array ([ 0 , 0 , 0 , 0 ]) return putmask ( mask , mask != find , replace ) mask = Image . open ( 'test.png' ) test ( mask ) What am I doing wrong? That gives me a ValueError: putmask: mask and data must be the same

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Lets say I have a simple 1D array with 10-20 entries. Some will be duplicate, How would I find out which entry is used the most? like.. $code = Array("test" , "cat" , "test" , "this", "that", "then"); How would I show "test" as the most used entry? 回答1: $code = Array("test" , "cat" , "test" , "this", "that", "then"); function array_most_common($input) { $counted = array_count_values($input); arsort($counted); return(key($counted)); } echo '<pre>'; print_r(array_most_common($code)); 回答2: You can get a count of the number of occurrences of

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have a 2D numpy array I want to find the 'every' location of all the unique elements. We can find the unique elements using numpy.unique(numpyarray.) . Here it comes the tricky part. Now I have to know all the locations for every unique element. Lets consider the following example. array([[1, 1, 2, 2],\ [1, 1, 2, 2],\ [3, 3, 4, 4],\ [3, 3, 4, 4]]) The result should be 1, (0,0),(1,1) 2, (0,2),(1,2) 3, (2,0),(3,1) 4, (2,2),(3,3) How to do it and what could be a suitable way to store and iterate over the values. It is to be noted that all the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Given an array of integers, find the first integer that is unique. my solution: use std::map put integer (number as key, its index as value) to it one by one (O(n^2 lgn)) , if have duplicate, remove the entry from the map (O(lg n)) , after putting all numbers into the map, iterate the map and find the key with smallest index O(n). O(n^2 lgn) because map needs to do sorting. It is not efficient. other better solutions? 回答1: I believe that the following would be the optimal solution, at least based on time / space complexity: Step 1: Store the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm trying to parse a string from JSON and turn those elements into an array in Javascript. Here's the code. var data = "{"fname":"Todd","lname":"James","cascade":"tjames","loc":"res","place":"home", "day0":"0,1,2,3,"}"; var getDay = data.day0; var getDayArray = getDay.split(","); Essentially, I'm trying to get day0, which is 0,1,2,3, and turn it into an array with a structure of [0] = 0 [1] = 1 [2] = 2 [3] = 3 What is the best way to go about doing this? 回答1: Something like this. Is that trailing comma intentional? var getDayArray = JSON

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I have a situation where I need to check if a constructor (X) has another constructor (Y) in its prototype chain (or is Y itself). The quickest means to do this might be (new X()) instanceof Y . That isn't an option in this case because the constructors in question may throw if instantiated without valid arguments. The next approach I've considered is this: const doesInherit = ( A , B ) => { while ( A ) { if ( A === B ) return true ; A = Object . getPrototypeOf ( A ); } return false ; } That works, but I can't shake the sense that

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Just trying to do a simple linear regression but I'm baffled by this error for: regr = LinearRegression() regr.fit(df2.iloc[ 1 : 1 000, 5].values, df2.iloc[ 1 : 1 000, 2].values) which produces: ValueError: Found arrays with inconsistent numbers of samples: [ 1 999] These selections must have the same dimensions, and they should be numpy arrays, so what am I missing? 回答 1 : It looks like sklearn requires the data shape of (row number, column number). If your data shape is (row number, ) like (999, ) , it does not work. By using numpy.reshape

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Possible Duplicates: Sizeof an array in the C programming language? determine size of array if passed to function How can I get the size of a C++ array that is passed to a function? In the following code, the sizeof(p_vertData) does not return the correct size of the array. float verts[] = { -1.0,1.0,1.0, 1.0,1.0,1.0, 1.0,-1.0,1.0, -1.0,-1.0,1.0, -1.0,1.0,-1.0, 1.0,1.0,-1.0, 1.0,-1.0,-1.0, -1.0,-1.0,-1.0 }; void makeVectorData(float p_vertData[]) { int num = (sizeof(p_vertData)/sizeof(int)); cout What am I doing wrong? 回答1: You can't -