Python_连接List与分割字符串_join&split

本文介绍了Python中字符串对象的join()和split()方法的使用技巧。join()方法可以将列表中的字符串元素连接成一个新字符串,而split()则可以将字符串分割为列表。通过实例展示了如何利用这些方法高效地处理字符串。

字符串对象的 join() 方法

join 只能用于元素是字符串的 list;它不进行任何的强制类型转换。连接一个存在一个或多个非字符串元素的 list 将引发一个异常

 

>>> params = {"server":"mpilgrim", "database":"master", "uid":"sa", "pwd":"secret"}

>>> ["%s=%s" % (k, v) for k, v in params.items()]

['server=mpilgrim', 'uid=sa', 'database=master', 'pwd=secret']

>>> ";".join(["%s=%s" % (k, v) for k, v in params.items()])

'server=mpilgrim;uid=sa;database=master;pwd=secret'

 

split 与 join 正好相反,它将一个字符串分割成多元素 list。

>>> s='server=mpilgrim;uid=sa;database=master;pwd=secret'

>>> s.split(";")

['server=mpilgrim', 'uid=sa', 'database=master', 'pwd=secret']

>>> s.split(";", 1)  # split 接受一个可选的第二个参数,它是要分割的次数

['server=mpilgrim', 'uid=sa;database=master;pwd=secret']

# 创建一个全局的循环队列以及全局共享变量 from queue import Queue global_data=[] global_queue = Queue() from datetime import datetime from threading import Thread import serial, re, math from flask import Flask, render_template, request, jsonify from pyecharts import options as opts from pyecharts.charts import Line import matplotlib.pyplot as plt import numpy from kalman5 import * from wifilib import * import mysql.connector from random import randrange from flask import Flask, render_template from pyecharts import options as opts from pyecharts.charts import Line app = Flask(__name__, static_folder="templates") app.config['MYSQL_HOST'] = 'localhost' # MySQL 主机名 app.config['MYSQL_USER'] = 'root' # MySQL 用户名 app.config['MYSQL_PASSWORD'] = '123123' # MySQL 密码 app.config['MYSQL_DB'] = 'csi' # MySQL 数据库名 def get_db_connection(): connection = mysql.connector.connect( host=app.config['MYSQL_HOST'], user=app.config['MYSQL_USER'], password=app.config['MYSQL_PASSWORD'], database=app.config['MYSQL_DB'], ) return connection # 返回的是数据库链接对象 def Line_base(index) -> Line: # index = int(index) # path = r'csi9.dat' # bf = read_bf_file_new(path,index) # csi_list = list(map(get_scale_csi, bf)) # print("test") # print(csi_list) # csi_np = (np.array(csi_list)) # csi_amp = np.abs(csi_np) # csi_total = numpy.empty(csi_amp[:, 0, 0, 25].shape) # csi_total_a = numpy.empty(csi_amp[:, 0, 0, 25].shape) # for i in range(6): # csi_total = csi_total + csi_amp[:, 0, 0, i + 15] # csi_total = csi_amp[:, 0, 0, 15] # csi_total_a = kalman_filter1(csi_amp[:, 0, 0, 15]) global_data.clear() for i in range(51): global_data.append(global_queue.get()) # print(global_data) csi_total_a = kalman_filter1(global_data) csi_total_a = csi_total_a[3:51] list2 = [str(i) for i in range(0, 48)] c = ( Line() .add_xaxis(list2) # .add_yaxis("波形1", csi_total[0:50],is_smooth='spline',is_symbol_show=False,color='blue') .add_yaxis("波形1", csi_total_a[0:48], is_smooth='spline', is_symbol_show=False, color='blue') .set_global_opts(title_opts=opts.TitleOpts(title="入侵检测系统", subtitle="实时波形检测"), yaxis_opts=opts.AxisOpts(max_=80, min_=0) ) ) return c @app.route("/") def index(): return render_template("index.html") @app.route("/LineChart") def get_Line_chart(): index = request.args.get('index') c = Line_base(index) return c.dump_options_with_quotes() @app.route("/getCount") def getCountAndIn(): index = request.args.get("index2") # print(index) state = getCountAndIN(index) # 返回一个包含入侵事件计数的JSON响应 return jsonify({'count': state}) @app.route('/get_alarm_history', methods=['GET']) def get_alarm_history(): try: connection = get_db_connection() cursor = connection.cursor() cursor.execute("SELECT date, type, description FROM alarm_history ORDER BY date DESC") history_data = cursor.fetchall() cursor.close() return jsonify({'data1': history_data}) except Exception as e: return jsonify({'error': str(e)}) import matplotlib.pyplot as plt import numpy import threading from wifilib import * from kalman5 import * from fancha import * import time import smtplib from email.mime.text import MIMEText from email.utils import formataddr plt.rcParams['font.sans-serif'] = ['SimHei'] plt.rcParams['axes.unicode_minus'] = False my_sender = '3284306656@qq.com' # 发件人邮箱账号 my_pass = 'bmjvijanuogzchbc' # 发件人邮箱授权码 my_user = '3377646378@qq.com' # 收件人邮箱账号,我这边发送给自己 def mail(): ret = True try: msg = MIMEText('有人入侵请注意!!!!!!', 'plain', 'utf-8') msg['From'] = formataddr(["XXX", my_sender]) msg['To'] = formataddr(["XXX", my_user]) msg['Subject'] = "测试报告" server = smtplib.SMTP_SSL("smtp.qq.com", 465) # 发件人邮箱中的SMTP服务器,端口是25 server.login(my_sender, my_pass) server.sendmail(my_sender, [my_user, ], msg.as_string()) # server.quit() except Exception: ret = False # print(1) # global_data def getCountAndIN(offset): # path = r'csi8.dat' # offset = int(offset) # date = numpy.empty([1, 7]) # bf = read_bf_file_new2(path, offset) # csi_list = list(map(get_scale_csi, bf)) # csi_np = (np.array(csi_list)) # csi_amp = np.abs(csi_np) # csi_total = numpy.empty(csi_amp[:, 0, 0, 8].shape) # for i in range(6): # csi_total = csi_total + csi_amp[:, 0, 0, i] # date = kalman_filter1(csi_amp[:, 0, 0, 8]) # print("test_data",date) data = kalman_filter1(global_data) data=data[3:50] # print(data) print(dynamic_variance1(data)) if detect_intrusion(dynamic_variance1(data)) == "intrusion": intrusion_date = datetime.now() intrusion_type = "无源入侵" intrusion_description = "有人入侵您的家" connection = get_db_connection() cursor = connection.cursor() sql = "INSERT INTO alarm_history (date, type, description) VALUES (%s, %s, %s)" cursor.execute(sql, (intrusion_date, intrusion_type, intrusion_description)) connection.commit() cursor.close() connection.close() threading.Thread(target=mail()).start() ##邮箱及授权码请自行配置,在SendMail下 return "intrusion" else: return "nobody" def get_csi_data(port): print("多线程1运行中…………") ser = serial.Serial(port=port, baudrate=921600, bytesize=8, parity='N', stopbits=1, timeout=0.1) pattern = r"\"\[(-?\d+,-?\d+)(,\s*-?\d+,-?\d+)*\]\"" while True: if ser.in_waiting > 0: data = ser.readline().decode('utf-8').strip() match = re.search(pattern, data) if match: str_data = match.group(0) # 提取整个匹配项,包括引号 # list_data = str_data[1:-1] # 去掉外面的引号 data_string = str_data[2:-2] # 使用split方法按逗号分割字符串,并使用列表推导式将每个字符串转换为整数 numbers_list = [int(num) for num in data_string.split(',')] tmp_results = [] for i, j in zip(numbers_list[2::2], numbers_list[3::2]): # 将数据添加到结果列表,63个 tmp_results.append(math.sqrt(i * i + j * j)) global_queue.put(variance(tmp_results)) # print(variance(tmp_results)) def variance(list): avg = sum(list) / len(list) sum_number = 0 for i in list: sum_number += (i - avg) ** 2 return round(sum_number / len(list)) # def get_data(): # print("多线程2运行中…………") # while(global_queue.qsize()>=50): # global_data.clear() # for i in range(51): # global_data.append(global_queue.get()) port = "COM3" th1 = Thread(target=get_csi_data, args=(port,)) th1.start() if __name__ == "__main__": try: # th1 = Thread(target=get_csi_data, args=(port,)) # th1.start() app.run() except Exception: input("输入任意字符串结束") th1.join() 解释这串python代码
最新发布
06-12
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