S = [“a”,”b”,”c”,”d”,”e”] 输出对数组S的排列A(5,3)用Python代码编写

以下是 Python 代码实现：

import itertools

S = ["a", "b", "c", "d", "e"]
A = list(itertools.permutations(S, 3))
print(A)

这里使用了 Python 内置的 itertools 模块的 permutations 函数，可以方便地生成指定长度的排列。传入的参数为原始数组和需要生成的排列长度，函数会返回一个生成器对象，可以将其转换为列表。

相关问题

求一个数组X，其中X中的元素是S中的字母按照a,..,z的顺序排列(利 用Sort函数,lower函数）。求数组Y，其中Y(1)表示a出现的次数， Y(2)表示b出现的次数......S = 'Scientists look for universal patterns of complex systems because such invariant features may help to unveil the principles of system organization Complex network studies can not only provide a unique viewpoint of nature and society but also reveal ubiquitous patterns, e.g. small world and scale free, characteristic of various complex systems. However, ecological studies have shown that binary food webs, which depict trophic interactions in ecosystems, refuse to become part of the small world and scale free networks family. Although some common features, including "two degrees separation", which means the very small average distance, are shared among food webs, other meaningful attributes such as degree distribution and clustering coefficient change with the size and complexity (connectance)of the network.';

首先，我们可以将字符串S转换为小写字母，并将其存储在数组X中。然后，使用sort函数对数组X进行排序。接下来，我们可以使用循环来计算每个字母在数组X中出现的次数，并将结果存储在数组Y中。

以下是实现这个过程的代码：

S = 'Scientists look for universal patterns of complex systems because such invariant features may help to unveil the principles of system organization Complex network studies can not only provide a unique viewpoint of nature and society but also reveal ubiquitous patterns, e.g. small world and scale free, characteristic of various complex systems. However, ecological studies have shown that binary food webs, which depict trophic interactions in ecosystems, refuse to become part of the small world and scale free networks family. Although some common features, including "two degrees separation", which means the very small average distance, are shared among food webs, other meaningful attributes such as degree distribution and clustering coefficient change with the size and complexity (connectance)of the network.';

% 将字符串S转换为小写字母
S = lower(S);

% 将字符串S中的字母存储在数组X中
X = [];
for i = 1:length(S)
    if isletter(S(i))
        X = [X S(i)];
    end
end

% 使用sort函数对数组X进行排序
X = sort(X);

% 初始化数组Y
Y = zeros(1, 26);

% 计算每个字母在数组X中出现的次数
for i = 1:length(X)
    index = double(X(i)) - 96; % 计算字母在字母表中的索引（a对应1，b对应2，依此类推）
    Y(index) = Y(index) + 1; % 对应索引位置的元素加1
end

% 显示数组Y中每个字母出现的次数
for i = 1:length(Y)
    fprintf('%c出现的次数：%d\n', char(i+96), Y(i));
end

执行以上代码后，将输出每个字母在字符串S中出现的次数。

统计学生成绩 输入学生的姓名和成绩 按成绩从高到低排列 输出 Student name grade setname setgradeO.getname Ogetgrade五个成员函数 主函数中定义学生类对象数组

以下是一个简单的实现：

#include <iostream>
#include <algorithm> // 用于排序
#include <string>

using namespace std;

class Student {
private:
    string name;
    int grade;
public:
    Student(string n, int g) {
        name = n;
        grade = g;
    }
    string getName() {
        return name;
    }
    int getGrade() {
        return grade;
    }
};

bool cmp(Student a, Student b) { // 比较函数，用于排序
    return a.getGrade() > b.getGrade(); // 按成绩从高到低排列
}

int main() {
    const int N = 5; // 定义学生类对象数组的大小
    Student s[N] = {
        Student("A", 90),
        Student("B", 85),
        Student("C", 77),
        Student("D", 92),
        Student("E", 81)
    }; // 初始化学生类对象数组

    sort(s, s + N, cmp); // 排序

    for (int i = 0; i < N; i++) { // 输出
        cout << "Student name: " << s[i].getName() << endl;
        cout << "Grade: " << s[i].getGrade() << endl;
    }

    return 0;
}

在主函数中，我们首先定义了一个大小为 5 的学生类对象数组，然后通过初始化的方式为每个学生类对象赋值。接着，我们调用 `sort()` 函数对学生类对象数组进行排序，排序方式是按成绩从高到低排列。最后，我们通过循环输出每个学生类对象的姓名和成绩。