Question

在显示从左下角开始（x，y）=（0,0）的2D数组时，我需要帮助。

这是我到目前为止所拥有的，我无法将左下角设为（0,0）。我拥有的是

x1y1，x1y2，x1y3，x1y4，x1y5，

x2y1，x2y2，x2y3，x2y4，x2y5，

x3y1，x3y2，x3y3，x3y4，x3y5，

x4y1，x4y2，x4y3，x4y4，x4y5，

x5y1，x5y2，x5y3，x5y4，x5y5，

我想拥有

x1y5，x2y5，x3y5，x4y5，x5y5，

x1y4，x2y4，x3y4，x4y4，x5y4，

x1y3，x2y3，x3y3，x4y3，x5y3，

x1y2，x2y2，x3y2，x4y2，x5y2，

x1y1，x2y1，x3y1，x4y1，x5y1，

#include <iostream>
#include <sstream>
#include <string>

using namespace std;

string ** array2D = nullptr;

void init2DArray(int, int);
void populate2DArray (int, int);
void display2DArray (int, int);
void safelyDeallocateMemory (int, int);

int main() {
   int row, col;
   row = col = 0;
   cout << "Pls enter no. of cols : ";
   cin >> col;
   cout << endl;

   cout << "Pls enter no. of rows : ";
   cin >> row;
   cout << endl;

    init2DArray (col, row);
    populate2DArray (col, row);
    display2DArray (col, row);
    safelyDeallocateMemory (col, row);

    cout << endl;

  return 0;
 }

void init2DArray (int col, int row) {
        array2D = new string * [row];

        for (int i = 0; i < row; i++)
              array2D [i] = new string [col];
}

void populate2DArray (int col, int row) {
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {

                ostringstream oss;
                oss << "x" << i + 1 << "y" << j + 1;

                array2D [i][j] = oss.str();
             }
         }
  }

void display2DArray (int col, int row) {
        cout << endl;
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {
                cout << array2D [i][j] << ", ";
            }
            cout << endl;
        }
 }

Answer 1

df1 = df.groupby(pd.Grouper(freq='D')).agg({'var1': 'mean','var2': ['mean', 'size']}) 
df1.columns = df1.columns.map('_'.join)
df1 = df1.rename(columns={'var2_size':'count'})
print (df1)
            var1_mean  var2_mean  count
2012-04-05   3.992166   4.968410      3
2012-04-06   6.843105   6.193568      5
2012-04-07   4.568436   3.135089      1

您应该做一些小事情。将字符串推入r = df.resample('D') df1 = r.mean().add_suffix('_mean').join(r.size().rename('count')) print (df1) var1_mean var2_mean count 2012-04-05 7.840487 6.885030 3 2012-04-06 4.762477 5.091455 5 2012-04-07 2.702414 6.046200 1时，必须将for (int i = 0; i < row; i++) { for (int j = 0; j < col; j++) { ostringstream oss; oss << "x" << j + 1 << "y" << (row - i); array2D [i][j] = oss.str(); } }附加到oss上，因为首先要执行内部循环。对于j + 1，您只需要将x更改为y；由于formula从(row - i)开始，您可以拥有i。如果0是5, 4, 3, 2, 1，则您有row，则下一次迭代您将有5，并且如此。

创建具有x y坐标的动态2D数组，例如图形

1 个答案: