wps2000 |
2016-10-12 18:46 |
解决第4章例子“70行货币转换程序”对PyQt5+Python3兼容性的问题
先上最初的源码: =================================================================== import sys import urllib2 from PyQt4.QtCore import * from PyQt4.QtGui import *
class Form(QDialog):
def __init__(self, parent=None): super(Form, self).__init__(parent)
date = self.getdata() rates = sorted(self.rates.keys())
dateLabel = QLabel(date) self.fromComboBox = QComboBox() self.fromComboBox.addItems(rates) self.fromSpinBox = QDoubleSpinBox() self.fromSpinBox.setRange(0.01, 10000000.00) self.fromSpinBox.setValue(1.00) self.toComboBox = QComboBox() self.toComboBox.addItems(rates) self.toLabel = QLabel("1.00") grid = QGridLayout() grid.addWidget(dateLabel, 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.connect(self.fromComboBox, SIGNAL("currentIndexChanged(int)"), self.updateUi) self.connect(self.toComboBox, SIGNAL("currentIndexChanged(int)"), self.updateUi) self.connect(self.fromSpinBox, SIGNAL("valueChanged(double)"), self.updateUi) self.setWindowTitle("Currency")
def updateUi(self): to = unicode(self.toComboBox.currentText()) from_ = unicode(self.fromComboBox.currentText()) amount = (self.rates[from_] / self.rates[to]) * \ self.fromSpinBox.value() self.toLabel.setText("%0.2f" % amount)
def getdata(self): # Idea taken from the Python Cookbook self.rates = {} try: date = "Unknown" fh = urllib2.urlopen("http://www.bankofcanada.ca" "/en/markets/csv/exchange_eng.csv") for line in fh: line = line.rstrip() if not line or line.startswith(("#", "Closing ")): continue fields = line.split(",") if line.startswith("Date "): date = fields[-1] else: try: value = float(fields[-1]) self.rates[unicode(fields[0])] = value except ValueError: pass return "Exchange Rates Date: " + date except Exception, e: return "Failed to download:\n%s" % e
app = QApplication(sys.argv) form = Form() form.show() app.exec_() =============================================================== 在最初的源码中,界面用是PyQt4,抓取数据用的是urllib2。在PyQT5中,connect方法已经改变了。在Python3.x中,urllib2已变成了urllib,使用方法也大不相同。首先,把原来的模块引入修改成:
import sys import re #引入了正则表达式模块 import urllib.request #把urllib2改成urllib from PyQt5.QtCore import * from PyQt5.QtGui import * from PyQt5.QtWidgets import * #QApplication 已经定位到PyQt5.QtWidgets这个模块
引入正则表达式模块,是因为要对原来的代码中的getdata方法进行修改。另外,在这几行中: self.connect(self.fromComboBox, SIGNAL("currentIndexChanged(int)"), self.updateUi) self.connect(self.toComboBox, SIGNAL("currentIndexChanged(int)"), self.updateUi) self.connect(self.fromSpinBox, SIGNAL("valueChanged(double)"), self.updateUi)
我前面说了,connect方法已经变了。要变成:
self.fromComboBox.currentIndexChanged.connect(self.updateUi) self.toComboBox.currentIndexChanged.connect(self.updateUi) self.fromSpinBox.valueChanged.connect(self.updateUi)
另外,还要把带有unicode的函数去掉,因为python3.x默认就是unicode编码。最后,修改后的完整代码就是这样:
=======================================================================================
import sys import re #引入了正则表达式模块 import urllib.request#把urllib2改成urllib from PyQt5.QtCore import * from PyQt5.QtGui import * from PyQt5.QtWidgets import * #QApplication 已经定位到PyQt5.QtWidgets这个模块
class Form(QDialog):
def __init__(self, parent=None): super(Form, self).__init__(parent)
date = self.getdata() rates = sorted(self.rates.keys())
dateLabel = QLabel(date) self.fromComboBox = QComboBox() self.fromComboBox.addItems(rates) self.fromSpinBox = QDoubleSpinBox() self.fromSpinBox.setRange(0.01, 10000000.00) self.fromSpinBox.setValue(1.00) self.toComboBox = QComboBox() self.toComboBox.addItems(rates) self.toLabel = QLabel("1.00") grid = QGridLayout() grid.addWidget(dateLabel, 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.fromComboBox.currentIndexChanged.connect(self.updateUi) self.toComboBox.currentIndexChanged.connect(self.updateUi) self.fromSpinBox.valueChanged.connect(self.updateUi) self.setWindowTitle("Currency")
def updateUi(self): to = self.toComboBox.currentText()#把unicode去掉 from_ = self.fromComboBox.currentText()#把unicode去掉 amount = (self.rates[from_] / self.rates[to]) * \ self.fromSpinBox.value() self.toLabel.setText("%0.2f" % amount)
def getdata(self): self.rates = {} try: date = "Unknown" fh = urllib.request.urlopen("http://www.bankofcanada.ca/en/markets/csv/exchange_eng.csv") csv_data = str(fh.read()) pattern = re.compile('Date[\s\S]*')#以"Date"关键词,匹配"Date"之后的数据 csv_data = pattern.search(csv_data) csv_data = csv_data.group(0) csv_data = csv_data.split("\\n")#以换行符为标志生成数据列表
for line in csv_data: if "Date" in line:#如果数据行包含“Date”项,就将最后的日期作为date的值 date = line.split(',')[-1]#以逗号进行分割,获得最后的日期 else: temp = line.split(',')#以逗号进行分割,获得每一行的数据,生成一个临时列表 if temp[0] is not "\'": key = temp[0]#将临时列表的第1项作为汇率名 value = temp[-1]#将这个列表的最后一项作为汇率值 self.rates[key] = float(value)#生成汇率字典
return "Exchange Rates Date: " + date except Exception as e: #在python3.x中,要将逗号改成as return "Failed to download:\n%s" % e
app = QApplication(sys.argv) form = Form() form.show() app.exec_()
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上述代码中,getdata方法改动最大,但也比较容易理解。关键是,能配合urllib对数据进行获取。 |
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