Conn=cat(1,Conn,p-1);
时间: 2024-03-18 08:45:03 浏览: 10
这行代码是 MATLAB 中的代码,它的作用是将一个数值 p 减去 1,然后将结果与一个矩阵 Conn 按列方向拼接起来,并将拼接后的矩阵重新赋值给 Conn 变量。具体来说,cat(1,Conn,p-1) 函数将 Conn 和 p-1 沿着列方向(即垂直方向)拼接为一个新的矩阵。这里的 1 表示列方向,如果是 2 则表示行方向。
相关问题
from bs4 import BeautifulSoup import requests import time import pymysql conn = pymysql.connect(host='localhost', user='root', password='123456', charset='utf8') cursor = conn.cursor() cursor.execute('create database wyya;') cursor.execute('use wyya;') create_Tb = 'create table sj(地址 varchar(100),标题 varchar(100),播放量 varchar(50),作者 varchar(50));' cursor.execute(create_Tb) headers = { 'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36' } for i in range(0, 1505, 35): print(i) time.sleep(2) url = 'https://music.163.com/discover/playlist/?cat=华语&order=hot&limit=35&offset=' + str(i)#修改这里即可 response = requests.get(url=url, headers=headers) html = response.text soup = BeautifulSoup(html, 'html.parser') # 获取包含歌单详情页网址的标签 ids = soup.select('.dec a') # 获取包含歌单索引页信息的标签 lis = soup.select('#m-pl-container li') print(len(lis)) for j in range(len(lis)): # 获取歌单详情页地址 url = ids[j]['href'] # 获取歌单标题 title = ids[j]['title'] # 获取歌单播放量 play = lis[j].select('.nb')[0].get_text() # 获取歌单贡献者名字 user = lis[j].select('p')[1].select('a')[0].get_text() # 输出歌单索引页信息 print(url, title, play, user) insert_Tb = 'insert into sj(地址,标题,播放量,作者) values(%s,%s,%s,%s);' val = (url, title, play, user) cursor.execute(insert_Tb, val) cursor.execute("select *from sj;") conn.commit(); data = cursor.fetchall() for bases in data: print(bases) conn.close()写出优化后的这段代码,使爬取到的所有数据全部存入数据库
from bs4 import BeautifulSoup
import requests
import time
import pymysql
# 连接数据库
conn = pymysql.connect(host='localhost', user='root', password='123456', charset='utf8')
cursor = conn.cursor()
# 创建数据库和表
cursor.execute('create database if not exists wyya;')
cursor.execute('use wyya;')
create_Tb = 'create table if not exists sj(地址 varchar(100),标题 varchar(100),播放量 varchar(50),作者 varchar(50));'
cursor.execute(create_Tb)
# 设置请求头
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36'
}
# 循环爬取歌单信息并存入数据库
for i in range(0, 1505, 35):
print(i)
time.sleep(2)
url = 'https://music.163.com/discover/playlist/?cat=华语&order=hot&limit=35&offset=' + str(i)
response = requests.get(url=url, headers=headers)
html = response.text
soup = BeautifulSoup(html, 'html.parser')
ids = soup.select('.dec a')
lis = soup.select('#m-pl-container li')
print(len(lis))
for j in range(len(lis)):
url = ids[j]['href']
title = ids[j]['title']
play = lis[j].select('.nb')[0].get_text()
user = lis[j].select('p')[1].select('a')[0].get_text()
print(url, title, play, user)
# 将爬取到的信息插入数据库
insert_Tb = 'insert into sj(地址,标题,播放量,作者) values(%s,%s,%s,%s);'
val = (url, title, play, user)
cursor.execute(insert_Tb, val)
# 查询并输出数据库中的数据
cursor.execute("select *from sj;")
data = cursor.fetchall()
for bases in data:
print(bases)
# 提交并关闭数据库连接
conn.commit()
conn.close()
My cat垂直分片过程代码
垂直分片的具体实现方式取决于所使用的数据库管理系统和编程语言。下面给出一个示例代码,假设我们使用MySQL数据库和Python编程语言来实现垂直分片。
首先,我们需要连接到MySQL数据库,并创建多个数据库,每个数据库负责处理对应的数据表。
```python
import mysql.connector
# 连接到MySQL数据库
conn = mysql.connector.connect(
host="localhost",
user="root",
password="password"
)
# 创建多个数据库
cursor = conn.cursor()
cursor.execute("CREATE DATABASE IF NOT EXISTS db1")
cursor.execute("CREATE DATABASE IF NOT EXISTS db2")
# 创建对应的数据表
cursor.execute("USE db1")
cursor.execute("CREATE TABLE IF NOT EXISTS table1 (id INT, name VARCHAR(255))")
cursor.execute("USE db2")
cursor.execute("CREATE TABLE IF NOT EXISTS table2 (id INT, age INT)")
```
然后,我们需要编写代码来将数据按照功能进行划分,并将其插入到对应的数据库中。
```python
# 从原始数据库中读取数据
cursor.execute("USE original_db")
cursor.execute("SELECT * FROM table1")
data1 = cursor.fetchall()
cursor.execute("SELECT * FROM table2")
data2 = cursor.fetchall()
# 将数据按照功能进行划分
data1_db1 = [(row[0], row[1]) for row in data1 if row[0] < 100]
data1_db2 = [(row[0], row[1]) for row in data1 if row[0] >= 100]
data2_db1 = [(row[0], row[1]) for row in data2 if row[1] < 30]
data2_db2 = [(row[0], row[1]) for row in data2 if row[1] >= 30]
# 将数据插入到对应的数据库中
cursor.execute("USE db1")
cursor.executemany("INSERT INTO table1 (id, name) VALUES (%s, %s)", data1_db1)
cursor.executemany("INSERT INTO table2 (id, age) VALUES (%s, %s)", data2_db1)
cursor.execute("USE db2")
cursor.executemany("INSERT INTO table1 (id, name) VALUES (%s, %s)", data1_db2)
cursor.executemany("INSERT INTO table2 (id, age) VALUES (%s, %s)", data2_db2)
# 提交事务
conn.commit()
```
以上代码仅为示例,具体实现方式可能因环境和需求而异。