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问题 I am using a module that can only be found in python 2.7, so when I run my script I have to specify python2.7 script instead of just script . I know there are bigger issues out there, but still I was wondering - is it possible, when writing a python script, to set the interpreter to 2.7 by default? Maybe by setting #! /usr/bin/env python for example? 回答1: Most unix environments will have the python2.7 executable, such that you can write: #!/usr/bin/env python2.7 Obviously this doesn't help

问题 How to set a conditional DEFAULT value to a column in oracle without using triggers? I want to achieve following needs: If "flag1"=1 then Default value to column Newfield must be "4". If "flag1"=2 then Default value to column Newfield must be "5". 回答1: That's what triggers are for. Use them. 回答2: A column DEFAULT is not allowed to reference another column, so this is not possible. You could perhaps just let the default remain as NULL, and then have a view to adjust it like: create view

问题 I need to tap default printer change notification, is it possible? My scenario is that I want to execute a command whenever default printer is changed in window. What my command does is, it just takes default printer information from registry and save it in HKLM. So, I have a service for this. Using this service, how can i tap notifications whenever a default printer is changed. I am using C++. 回答1: From a regular application, I would listen for a WM_SETTINGCHANGE message and then call

问题 Is there some way to set what the default representation for null values should be in Json.NET? More specifically null values inside an array. Given the class public class Test { public object[] data = new object[3] { 1, null, "a" }; } Then doing this Test t = new Test(); string json = JsonConvert.SerializeObject(t); Gives {"data":[1,null,"a"]} Is it possible to make it look like this? {"data":[1,,"a"]} Without using string.Replace. 回答1: Figured it out. I had to implement a custom

问题 The screenshot show 3 typical definitions of data type: id (autoincrement), a title and a number. 1.- Which are differences between: none and NULL ? 2.- Do I must choose as defined: '' for varchar types when I want an empty string? 3.- Do I must put an as defined: 0 default value for autoincrement int types? 回答1: Default none means there is no default value. If a value is not provided on an insert, the query will fail with a "no default value error". NULL is the actual NULL value meaning if

问题 This question already has answers here : “Least Astonishment” and the Mutable Default Argument (31 answers) Closed 6 years ago . I have the following setup: def returnList(arg=["abc"]): return arg list1 = returnList() list2 = returnList() list2.append("def") print("list1: " + " ".join(list1) + "\n" + "list2: " + " ".join(list2) + "\n") print(id(list1)) print(id(list2)) Output: list1: abc def list2: abc def 140218365917160 140218365917160 I can see that arg=["abc"] returns copy of the same

问题 Since updating to xCode 4.5, and with the release of the iPhone 5 with the 4" display, each time I create a new ViewController with a xib file, the xib defaults to a 4" display size. At the moment I'm working through Aaron Hillegass's excellent iOS Programming text. All the examples assume a 3.5" Xib. How do I get new views to be 3.5" instead of the taller skinny 4" default xib views? 回答1: Found the answer here: How to make a uitableview in interface builder compatible with a 4 inch iPhone

问题 I created a new non-sudo user(user1) in vagrant(Ubuntu 12.04 OS), and added the insecure public key to the user1 authorised key file. In vagrant file, added the default user as "user1" : config.ssh.default.username = "user1" Now vagrant up is failing with following error message: The following SSH command responded with a non-zero exit status. Vagrant assumes that this means the command failed! mkdir -p /vagrant Stdout from the command: Stderr from the command: sudo: no tty present and no

问题 A HTML page is created using JSF and facelets (xhtml). There are 2 h:forms that goes to different places. The user enters data on one form and presses the "Enter" key. Here is where it gets tricky. On IE 6 and above, either the forms action gets submitted (which usually points to the page you are on) which then just reloads the page, or the first h:commandbutton/link that is on the page. Its totally random, but its consistant on that page. Here is what I have tried, I tried placing the

问题 I have a page on which one dropdown as Report1 and Report2 is there. If I select Report1 it will populate startdate and enddate. I will select startdate and end date then cliick on view report it will do ajax call and fetch the data and displaying in table, I am using datatable for this. I have default sorting of the second coulmn and also I can able to sort other column. If I sort other column and then select the other report Report2 and then select startdate adn end date and then hit the