python - 在 python 方法中使用 np.genfromtxt 时出现问题

Question

我正在编写一个 python 脚本，它使用 PyQt 和 Matplotlib 来绘制 2D CSV 文件的图形。我仍在学习 python，所以我在解决一些错误时遇到了困难。尤其令我困扰的是

错误:

Traceback (most recent call last): File "C:/Users/jonesza/Documents/Python Scripts/2D-Graph/Qt_2D_Plot.py", line 62, in update_graph l, v = self.parse_file(self.mpllineEdit.text()) File "C:/Users/jonesza/Documents/Python Scripts/2D-Graph/Qt_2D_Plot.py", line 53, in parse_file names=['time','temperature']) File "C:\WinPython\python-2.7.5.amd64\lib\site-packages\numpy\lib\npyio.py", line 1356, in genfromtxt first_values = split_line(first_line) File "C:\WinPython\python-2.7.5.amd64\lib\site-packages\numpy\lib_iotools.py", line 208, in _delimited_splitter line = line.strip(asbytes(" \r\n")) AttributeError: 'QString' object has no attribute 'strip'

源代码:

# used to parse files more easily
from __future__ import with_statement

# Numpy module
import numpy as np

# for command-line arguments
import sys

# Qt4 bindings for core Qt functionalities (non-Gui)
from PyQt4 import QtCore
# Python Qt4 bindings for GUI objects
from PyQt4 import QtGui

# import the MainWindow widget from the converted .ui files
from qtdesigner import Ui_MplMainWindow

class DesignerMainWindow(QtGui.QMainWindow, Ui_MplMainWindow):
    """Customization for Qt Designer created window"""
    def __init__(self, parent = None):
        # initialization of the super class
        super(DesignerMainWindow, self).__init__(parent)
        # setup the GUI --> function generated by pyuic4
        self.setupUi(self)

        # connect the signals with the slots
        QtCore.QObject.connect(self.mplpushButton, QtCore.
SIGNAL("clicked()"), self.update_graph)
        QtCore.QObject.connect(self.mplactionOpen, QtCore.
SIGNAL("triggered()"), self.select_file)
        QtCore.QObject.connect(self.mplactionQuit, QtCore.
SIGNAL("triggered()"), QtGui.qApp, QtCore.SLOT("quit()"))

    def select_file(self):
        """opens a file select dialog"""
        # open the dialog and get the selected file
        file = QtGui.QFileDialog.getOpenFileName()
        # if a file is selected
        if file:
            # update the lineEdit text with the selected filename
            self.mpllineEdit.setText(file)

    def parse_file(self, filename):
        """gets first two columns from .csv uploaded"""
        #import data from .csv
        data = np.genfromtxt(filename, delimiter=',', 
                                  names=['time','temperature'])
        x = data['time']
        y = data['temperature']

        return x,y

    def update_graph(self):    
        """Updates the graph with new letteers frequencies"""
        # get the axes for the 2D graph
        l, v = self.parse_file(self.mpllineEdit.text())
        # clear the Axes
        self.mpl.canvas.ax.clear()
        # plot the axes
        self.mpl.canvas.ax.plot(l,v)
        # force an image redraw
        self.mpl.canvas.draw()

# create the GUI application
app = QtGui.QApplication(sys.argv)
# instantiate the main window
dmw = DesignerMainWindow()
# show it 
dmw.show()
# start the Qt main loop execution, exiting from this script
# with the same return code of Qt application
sys.exit(app.exec_())

提前感谢您的帮助。

Answer 1

我假设 self.mpllineEdit.text() 生成一个 QString。您需要在 PyQt 文档或交互式 shell 中探索它有哪些方法，以及是否需要执行任何操作将其转换为常规 Python 字符串。 genfromtxt 尝试将该字符串拆分为行，然后去掉行结束字符，以便它可以解析该行。

尝试:

self.parse_file(str(self.mpllineEdit.text()))

这可能会将 Qstring 转换为常规 Python 字符串。