大约有 47,000 项符合查询结果（耗时：0.0540秒） [XML]
How do I check if a variable exists?
...have nested functions, variables in outer scopes. If you want to check for all of them, you're probably best off triggering NameError after all.
– Petr Viktorin
Jun 10 '14 at 20:18
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Wait for a void async method
...
await Task.Run(() => An_async_void_method_I_can_not_modify_now())
– themefield
Mar 12 '19 at 21:46
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Difference between “git checkout ” and “git checkout -- ”
...his is not Git-specific, it's a general Unix command line convention. Normally you use it to clarify that an argument is a file name rather than an option, e.g.
rm -f # does nothing
rm -- -f # deletes a file named "-f"
git checkout1 also takes -- to mean that subsequent arguments are not ...
Code for Greatest Common Divisor in Python [closed]
... the result will have the same sign as b", hence gcd(1, -1) == -1 seems totally legit to me.
– Marco Bonelli
Jan 11 '15 at 2:30
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Auto-fit TextView for Android
...de
public void onClick(final View v) {
container.removeAllViews();
final int maxWidth = container.getWidth();
final int maxHeight = container.getHeight();
final AutoResizeTextView fontFitTextView = new AutoResizeTextView(MainActivity.this);
...
Split Python Flask app into multiple files
...like this:
Main.py
from flask import Flask
from AccountAPI import account_api
app = Flask(__name__)
app.register_blueprint(account_api)
@app.route("/")
def hello():
return "Hello World!"
if __name__ == "__main__":
app.run()
AccountAPI.py
from flask import Blueprint
account_api = Bl...
The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value
...orm (headline, story, and image). ApplyPropertyChanges applies changes to all properties of the object, including your uninitialized DateTime, which is set to 0001-01-01, which is outside of the range of SQL Server's DATETIME.
Rather than using ApplyPropertyChanges, I'd suggest retrieving the obje...
How to prevent a jQuery Ajax request from caching in Internet Explorer?
...
You can disable caching globally using $.ajaxSetup(), for example:
$.ajaxSetup({ cache: false });
This appends a timestamp to the querystring when making the request. To turn cache off for a particular $.ajax() call, set cache: false on it locally, ...
Difference between exit() and sys.exit() in Python
...raising SystemExit. sys.exit does so in sysmodule.c:
static PyObject *
sys_exit(PyObject *self, PyObject *args)
{
PyObject *exit_code = 0;
if (!PyArg_UnpackTuple(args, "exit", 0, 1, &exit_code))
return NULL;
/* Raise SystemExit so callers may catch it or clean up. */
PyE...
How to set default values in Rails?
...
"Correct" is a dangerous word in Ruby. There's usually more than one way to do anything. If you know you'll always want that default value for that column on that table, setting them in a DB migration file is the easiest way:
class SetDefault < ActiveRecord::Migration
...