Question

我有一些Python代码，使用Fabric上下文管理器，如：

with settings(warn_only=True), hide('running', 'stdout', 'stderr', 'warnings'):
    do_stuff()

每次运行时，Python都会给我DeprecationWarning：

With-statements now directly support multiple context managers
  with settings(warn_only=True), hide('running', 'stdout', 'stderr', 'warnings'):

为什么我收到此警告以及如何解决？

我有点困惑，因为this similar question暗示我正在使用嵌套管理器，并且修复是将它们重写为我已经使用的单行版本。

我尝试重新编写它：

with settings(warn_only=True) as a, hide('running', 'stdout', 'stderr', 'warnings') as b:
    do_stuff()

和

with settings(warn_only=True):
    with hide('running', 'stdout', 'stderr', 'warnings'):
        do_stuff()

但两人都给了我同样的警告。

Answer 1

似乎Fabric本身正在使用已弃用的import math import numpy as np from PyQt4 import QtGui from matplotlib.figure import Figure from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas class UsersPerCountryAndPlatformBar(FigureCanvas): def __init__(self, parent=None, width=5, height=4, dpi=100): fig = Figure(figsize=(width, height), dpi=dpi) FigureCanvas.__init__(self, fig) self.axes = fig.add_subplot(111) self.compute_initial_figure() def compute_initial_figure(self): A_B = [['Afghanistan', 'Albania', 'Algeria', 'American Samoa', 'Angola'], [1, 9, 7, 1, 1], [1, 7, 2, 0, 1], \ [0, 4, 3, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]] C_F = [['Cambodia', 'Canada', 'Chile', 'China', 'Colombia'], [13, 189, 12, 5, 10], [5, 115, 6, 64, 7], \ [1, 11, 1, 2, 4], [2, 12, 0, 2, 0], [2, 5, 0, 0, 0]] self.data = {"A_B" : A_B, "C_F" : C_F} self.updatefig("A_B") def updatefig(self, text): self.plot(self.data[text]) def plot(self, X_Y): self.axes.clear() summedX_Y = [] for i in range(len(X_Y[0])): summedX_Y.append(X_Y[1][i] + X_Y[2][i] + X_Y[3][i] + X_Y[4][i] + X_Y[5][i]) def roundup(x): return int(math.ceil(x / 10.0)) * 10 N = len(X_Y[0]) ind = np.arange(N) width = 0.75 colors = ['yellowgreen', 'paleturquoise', 'royalblue', 'lightsteelblue', 'firebrick'] print [x + y for x, y in zip(X_Y[1], X_Y[2])] print [x + y + z for x, y, z in zip(X_Y[1], X_Y[2], X_Y[3])] print [x + y + z + i for x, y, z, i in zip(X_Y[1], X_Y[2], X_Y[3], X_Y[4])] p1 = self.axes.bar(ind, X_Y[1], width, color = colors[0]) p2 = self.axes.bar(ind, X_Y[2], width, bottom = X_Y[1], color = colors[1]) p3 = self.axes.bar(ind, X_Y[3], width, bottom = [x + y for x, y in zip(X_Y[1], X_Y[2])], color = colors[2]) p4 = self.axes.bar(ind, X_Y[4], width, bottom = [x + y + z for x, y, z in zip(X_Y[1], X_Y[2], X_Y[3])], color = colors[3]) p5 = self.axes.bar(ind, X_Y[5], width, bottom = [x + y + z + i for x, y, z, i in zip(X_Y[1], X_Y[2], X_Y[3], X_Y[4])], color = colors[4]) self.axes.set_ylabel('Count') self.axes.set_title('Users Per Country And Platform') self.axes.set_xticks(ind) #self.axes.set_xticklabels(countrylabels, fontsize = 8) self.axes.set_yticklabels(np.arange(0, max(summedX_Y), roundup(max(summedX_Y) / 10))) self.axes.legend((p1[0], p2[0], p3[0], p4[0], p5[0]), ('Android', 'iOS', 'Windows', 'OS X', 'WebGL')) self.draw_idle() class Ui_MainWindow(object): def setupUi(self, MainWindow): self.main_widget = QtGui.QWidget(MainWindow) l = QtGui.QVBoxLayout(self.main_widget) self.main_widget.setFocus() MainWindow.setCentralWidget(self.main_widget) self.UPCP = UsersPerCountryAndPlatformBar(self.main_widget, width = 10, height = 5, dpi = 100) comboBox = QtGui.QComboBox(MainWindow) comboBox.addItem('A_B') comboBox.addItem('C_F') comboBox.activated[str].connect(self.UPCP.updatefig) l.addWidget(comboBox) l.addWidget(self.UPCP) if __name__ == "__main__": import sys app = QtGui.QApplication(sys.argv) MainWindow = QtGui.QMainWindow() ui = Ui_MainWindow() ui.setupUi(MainWindow) MainWindow.show() sys.exit(app.exec_())。

请参阅https://github.com/fabric/fabric/issues/1364

票证上的唯一建议似乎是忽略它，因为他们希望保持与旧版Python的向后兼容性。

Answer 2

全面解决方案是将其添加到程序顶部：

import warnings

warnings.simplefilter("ignore", DeprecationWarning)

基本上，这会停止显示任何DeprecationWarning。

这里有几个用于了解警告的链接。希望这会有所帮助！

https://docs.python.org/2.7/library/warnings.html

https://www.idiotinside.com/2016/12/17/python-warnings-framework/

如何修复语句弃用警告

2 个答案: