用PyQt5实现了界面，使用urllib实时抓取ip138.com网站的汇率信息。

import sys
import urllib
import urllib.request
from PyQt5.QtWidgets import *class Form(QDialog):def __init__(self, parent=None):super(Form, self).__init__(parent)self.getdata()comboItems = list(self.rates.keys())textLabel = QLabel('实时汇率查询换算')self.fromComboBox = QComboBox()self.fromComboBox.addItems(comboItems)self.fromSpinBox = QDoubleSpinBox()self.fromSpinBox.setRange(0.01, 10000000.00)self.fromSpinBox.setValue(100)self.toComboBox = QComboBox()self.toComboBox.addItems(comboItems)self.toLabel = QLabel('1.00')grid = QGridLayout()grid.addWidget(textLabel, 0, 0)grid.addWidget(self.fromComboBox, 1, 0)grid.addWidget(self.fromSpinBox, 1, 1)grid.addWidget(self.toComboBox, 2, 0)grid.addWidget(self.toLabel, 2, 1)self.setLayout(grid)self.updateUi()self.fromComboBox.currentIndexChanged.connect(self.updateUi)self.toComboBox.currentIndexChanged.connect(self.updateUi)self.fromSpinBox.valueChanged.connect(self.updateUi)self.setWindowTitle('汇率  @author : likui')def updateUi(self):from_value = self.rates[self.fromComboBox.currentText()]to_value = self.rates[self.toComboBox.currentText()]money = self.fromSpinBox.value()url = 'http://qq.ip138.com/hl.asp?from=%s&to=%s&q=%s' % (from_value, to_value, money)html = self.urlopen(url)table_start = html.find('<table')count = 5td_begin = html.find('<td')while count:count -= 1td_begin = html.find('<td', td_begin + 1)temp = td_begintd_end = html.find('</td>', td_begin)amount = float(html[td_begin + 4:td_end])self.toLabel.setText('%0.2f' % amount)def getdata(self):self.rates = {}url = 'http://qq.ip138.com/hl.asp'html = self.urlopen(url)td_begin = html.find('<td>')td_end = html.find('</td>', td_begin)resource = html[td_begin:td_end]begin = resource.find('<optgroup')end = resource.find('</optgroup>')option_begin = resource.find('<option', begin)while option_begin != -1:value = resource[option_begin + 14:option_begin + 17]value_begin = resource.find('>', option_begin)value_end = resource.find('<', value_begin)rate = resource[value_begin + 1:value_end]self.rates[rate] = valueoption_begin = resource.find('<option', value_end)if option_begin > end:breakdef urlopen(self, url):ret = urllib.request.Request(url)ret.add_header('User-Agent', 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) ''Chrome/41.0.2272.101 Safari/537.36')html = urllib.request.urlopen(ret).read().decode('GB2312')return htmlif __name__ == '__main__':app = QApplication(sys.argv)form = Form()form.show()app.exec_()