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问题 This question already has answers here : Closed 9 years ago . Possible Duplicate: “Least Astonishment” in Python: The Mutable Default Argument I am using the Python IDE PyCharm and something that is have by default is it will showing warning when I have a mutbale type as a default value. For example, when I have this: def status(self, options=[]): PyCharm wants it to looks like: def status(self, options=None): if not options: options = [] My question is whether or not this is a standard way

问题 It appears that the pandas to_csv function only allows single character delimiters/separators. Is there some way to allow for a string of characters to be used like, "::" or "%%" instead? I tried: df.to_csv(local_file, sep = '::', header=None, index=False) and getting: TypeError: "delimiter" must be a 1-character string 回答1: Use numpy-savetxt Ex: np.savetxt(file.csv, np.char.decode(chunk_data.values.astype(np.bytes_), 'UTF-8'), delimiter='~|', fmt='%s',encoding=None) np.savetxt(file.dat,

问题 What does this error mean? I have trouble googling any docs. The code worked fine and suddenly broke after restarting windows. I looked in the process monitor and the DLL is found and accessed without any permission errors File "c:\Python27\lib\ctypes\__init__.py", line 435, in __getattr__ dll = self._dlltype(name) File "c:\Python27\lib\ctypes\__init__.py", line 365, in __init__ self._handle = _dlopen(self._name, mode) WindowsError: [Error 127] The specified procedure could not be found 回答1:

问题 In my rails app I've decided to use singleton to create some sort of factory to get objects properly. config/initializers/registry.rb: registry = Registry.instance registry.define_lazy :period_predictor do PeriodPredictor.new(NotificationBuilder.new, 28, 4, 3) end registry.define_lazy :notification_sender do NotificationSender.new end lib/registry.rb: # Registry class which is singleton and stores values. class Registry include Singleton # Define simple value. Like a constant. # # @param key

问题 how can i change the fore color of the chart labels? here's a screenshot of the chart i tried using the chart1.series[0].FontForeColor = color.white; but the entire chart turns white. 回答1: Try this: this.chart1.BackColor = Color.AliceBlue; this.chart1.ChartAreas[0].AxisX.LineColor = Color.Red; this.chart1.ChartAreas[0].AxisX.MajorGrid.LineColor = Color.Red; this.chart1.ChartAreas[0].AxisX.LabelStyle.ForeColor = Color.Red; this.chart1.ChartAreas[0].AxisY.LineColor = Color.Red; this.chart1

问题 I want to delete an element from an array that I am displaying as a list using a ForEach , but I also need to send a HTTP request to a REST API and I need to put the index of the element in the body of the request. Here is my code: ForEach(self.symptoms, id: \.self) { symptom in VStack(alignment: .leading) { Text(symptom) } }.onDelete(perform: delete) Here is the delete function: func delete(at offsets: IndexSet) { self.symptoms.remove(atOffsets: offsets) // here I want to make the HTTP

问题 Lets say that i make a websocket server chat (node.js + socket.io). How would i store the chat messages, so that when a "new" user joins the chat, he will be seeing old chat messages, and not just the ones which has been sent while hes in the chat. Should the data be stored in variables in the server? Something like: var io = require('socket.io').listen(80); var saveData = { }; io.sockets.on('connection', function (socket) { socket.emit('news', { hello: 'world' }); socket.on('my other event',

问题 What does this error mean? I have trouble googling any docs. The code worked fine and suddenly broke after restarting windows. I looked in the process monitor and the DLL is found and accessed without any permission errors File "c:\Python27\lib\ctypes\__init__.py", line 435, in __getattr__ dll = self._dlltype(name) File "c:\Python27\lib\ctypes\__init__.py", line 365, in __init__ self._handle = _dlopen(self._name, mode) WindowsError: [Error 127] The specified procedure could not be found 回答1:

问题 how can i change the fore color of the chart labels? here's a screenshot of the chart i tried using the chart1.series[0].FontForeColor = color.white; but the entire chart turns white. 回答1: Try this: this.chart1.BackColor = Color.AliceBlue; this.chart1.ChartAreas[0].AxisX.LineColor = Color.Red; this.chart1.ChartAreas[0].AxisX.MajorGrid.LineColor = Color.Red; this.chart1.ChartAreas[0].AxisX.LabelStyle.ForeColor = Color.Red; this.chart1.ChartAreas[0].AxisY.LineColor = Color.Red; this.chart1

问题 I'm trying to generate a UI element that is dynamic based on how the user wishes to provide their input. I'm using the Shiny Dashboard for simplicity but I have encountered an issue with the sidebarMenu. Previously when I was placing static UI elements directly into the sidebarMenu, I had no issue, however when trying to place dynamic UI elements into the sidebarMenu I have problems. I'm using R 3.3.2 and Shiny 1.0.0 and Dashboard 0.5.3. The specific problem I have is that when the program