arrays

问题 I know that the following is not correct: int arr[2][3] = {}; //some array initialization here int** ptr; ptr = arr; But I am quite surprised that the following lines actually work int arr[2][3] = {}; //some array initialization here auto ptr = arr; int another_arr[2][3] = {}; //some array initialization here ptr = another_arr; Can anyone possibly explain what is the type assigned to ptr in the second block of code, and what happened underneath? 回答1: Well, arrays decay to pointers when used

问题 Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . Improve this question Where is the mistake in my code? package My; import java.text.SimpleDateFormat; import java.util.Date; public class Hello { public static void main(String[] args) { Date now = new Date(); SimpleDateFormat formatter = new SimpleDateFormat("MMM/dd/yyyy HH:mm:ss");

问题 I have an array in the form [ ['16-24', 192081], ['16-24', 94452], ['16-24', 1055], ['25-34', 192081], ['25-34', 94452], ['25-34', 1055], ... ] I have many items in the array that I'd like to reduce down to the unique left-hand entries. This is an example of what I'd like to reduce down to [ ['16-24', 287588], ['25-34', 287588], ... ] Obviously the numbers here are a contrived example. I've looked into javascript's array reduce but I'm unsure how to use it to achieve this effect 回答1: Use

问题 I have an array in the form [ ['16-24', 192081], ['16-24', 94452], ['16-24', 1055], ['25-34', 192081], ['25-34', 94452], ['25-34', 1055], ... ] I have many items in the array that I'd like to reduce down to the unique left-hand entries. This is an example of what I'd like to reduce down to [ ['16-24', 287588], ['25-34', 287588], ... ] Obviously the numbers here are a contrived example. I've looked into javascript's array reduce but I'm unsure how to use it to achieve this effect 回答1: Use

问题 The error shows in my last two codes. ValueError: Expected 2D array, got 1D array instead: array=[0 1]. Reshape your data either using array.reshape(-1, 1) if your data has a single feature or array.reshape(1, -1) if it contains a single sample. import numpy as np import pandas as pd from sklearn.model_selection import ShuffleSplit %matplotlib inline df = pd.read_csv('.......csv') df.drop(['Company'], 1, inplace=True) x = pd.DataFrame(df.drop(['R&D Expense'],1)) y = pd.DataFrame(df['R&D

问题 I have an array of objects that looks like the image below. Is there a way by which I can have an array that contains unique objects with respect to id ? We can see below that the id are same at index [0] and index [2]. Is there a way that I can get an array containing objects with unique id and the first object from the last index is added to the unique array rather than the first object. In this case, Object at index[2] should be added instead of object at index[0]: 回答1: To get an array of

问题 I am working on a problem and my output is something like this: List with long string inside it ["21:15-21:30 IllegalAgrumentsException 1, 21:15-21:30 NullPointerException 2, 22:00-22:15 UserNotFoundException 1, 22:15-22:30 NullPointerException 1 ....."] I need to convert the data in something like this: response: [ { "time": "21:15-21:30", "logs": [ { "exception": "IllegalAgrumentsException", "count": 1 },{ "exception": "NullPointerException", "count": 2 } ] }, { "time": "22:00-22:15", "logs

问题 I have an array which consists of 7 days names. This array will be dynamic everytime. So i want to check which day is missing from an array. For ex, [Monday,Tuesday,Thursday,Friday,Saturday,Sunday] Here, the wednesday is missing so output should be wednesday Sometimes there will be more then one day will be missing and sometimes none, so the output should be and array which will contain all missing days. 回答1: you can compare two arrays with array_diff . Example: https://3v4l.org/4g00a 回答2:

问题 I have an array that I loop through with for each loop it returns only the first iteration but if I change it to echo it prints all of them to the screen, new to PHP not sure why is it acting this way tried looking for an answer but did not find one. the code below: function getData($values){ foreach ($values as $key => $value){ return "<p>". $key . " " . $value ."</p></br>"; } } $SubmitedResult->SerialisedForm = getData($data); 回答1: return always exits the function and returns its argument.

问题 I have an array which consists of 7 days names. This array will be dynamic everytime. So i want to check which day is missing from an array. For ex, [Monday,Tuesday,Thursday,Friday,Saturday,Sunday] Here, the wednesday is missing so output should be wednesday Sometimes there will be more then one day will be missing and sometimes none, so the output should be and array which will contain all missing days. 回答1: you can compare two arrays with array_diff . Example: https://3v4l.org/4g00a 回答2: