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问题 I have a sinusoid with length 5 seconds as below: x=sin(0:.01:2*pi*500*5); Now I would like to hear the audio of this waveform by giving a command similar as below: playsound(x,samplingfrequency); It will be useful for me if I could write this audio data to a wav or mp3 file. What is the library needed and the equivalent command in julia for this functionality? 回答1: You may play audio with https://github.com/ssfrr/AudioIO.jl And for write/read wav https://github.com/JuliaLang/Sound.jl/blob

问题 I use c++11 while I need some classes from c++17 library. When using boost from which classes were added I wish to do the following: #if __cplusplus < CPP17 using std::any = boost::any; #endif Such alias is not allowed. Also extending the std namespace causes undefined behaviour. I wish my code to look the same regardles of the c++ version. Is there a clear way? 回答1: The clear way is to add a customized name for it. #if __cplusplus < CPP17 using my_any = boost::any; #else using my_any = std:

问题 public static int[,] operator *(int[,] arr1, int[,] arr2) { int sum; int[,] res = new int[arr1.GetLength(0), arr2.GetLength(1)]; for (int i = 0; i < arr1.GetLength(0); i++) { for (int j = 0; j < arr2.GetLength(1); j++) { sum = 0; for (int k = 0; k < arr1.GetLength(1); k++) { sum = sum + (arr1[i, k] * arr2[k, j]); } res[i, j] = sum; //Console.Write("{0} ", res[i, j]); } //Console.WriteLine(); } return res; } Here i am trying to overload * operator to multiply two matrices.. but the compiler

问题 With the update react native to version 0.63 , new components have appeared. Can someone more experienced explain how the Pressable differs from the TouchableOpacity and when it is better to use them. 回答1: Pressable was a new introduction to RN 0.63, prior to that,Touchable Opacity was the most common used Component to wrap a component or simliar components. Both their basic functionalities are same, to make a text/image clickable and user interactive. But with Pressable you get to access a

问题 public static int[,] operator *(int[,] arr1, int[,] arr2) { int sum; int[,] res = new int[arr1.GetLength(0), arr2.GetLength(1)]; for (int i = 0; i < arr1.GetLength(0); i++) { for (int j = 0; j < arr2.GetLength(1); j++) { sum = 0; for (int k = 0; k < arr1.GetLength(1); k++) { sum = sum + (arr1[i, k] * arr2[k, j]); } res[i, j] = sum; //Console.Write("{0} ", res[i, j]); } //Console.WriteLine(); } return res; } Here i am trying to overload * operator to multiply two matrices.. but the compiler

问题 public static int[,] operator *(int[,] arr1, int[,] arr2) { int sum; int[,] res = new int[arr1.GetLength(0), arr2.GetLength(1)]; for (int i = 0; i < arr1.GetLength(0); i++) { for (int j = 0; j < arr2.GetLength(1); j++) { sum = 0; for (int k = 0; k < arr1.GetLength(1); k++) { sum = sum + (arr1[i, k] * arr2[k, j]); } res[i, j] = sum; //Console.Write("{0} ", res[i, j]); } //Console.WriteLine(); } return res; } Here i am trying to overload * operator to multiply two matrices.. but the compiler

问题 I am writing a service based app with a bound service, and the service's onBind() method never seems to be called (testing it with Toasts and Logs). The service: import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.app.Service; import android.content.Context; import android.content.Intent; import android.location.Criteria; import android.location.Location; import android.location.LocationListener; import android.location

问题 I have a sinusoid with length 5 seconds as below: x=sin(0:.01:2*pi*500*5); Now I would like to hear the audio of this waveform by giving a command similar as below: playsound(x,samplingfrequency); It will be useful for me if I could write this audio data to a wav or mp3 file. What is the library needed and the equivalent command in julia for this functionality? 回答1: You may play audio with https://github.com/ssfrr/AudioIO.jl And for write/read wav https://github.com/JuliaLang/Sound.jl/blob

问题 I've got a big database with analytics data written in JSON. I want to filter out rows with incorrect data: invalid json (some rows has something like that: '{"hello": "world' some attributes is not array so it would take '{"products": [1,2,3]}' and will leave out the '{"products": 1}' I want to do something like that: select * from analytics where (is_correct_json(json::json)) and (is_array(json::json->>'products')) How can I achieve that? 回答1: This is another good example why choosing the

问题 I have .zip archive with filename.xlsx inside it and I want to parse Excel sheet line by line. How to proper pass filename into pandas.read_excel in this case? I tried: import zipfile import pandas myzip=zipfile.ZipFile(filename.zip) for fname in myzip.namelist(): with myzip.open(fname) as from_archive: with pandas.read_excel(from_archive) as fin: for line in fin: .... but it doesn't seem to work, and the result was: AttributeError: __exit__ 回答1: You can extract your zip-file into a variable