大约有 40,000 项符合查询结果（耗时：0.0429秒） [XML]
Referring to the null object in Python
...
SyntaxError: cannot assign to keyword
It's therefore safe to assume that all None references are the same. There isn't any "custom" None.
To test for None use the is operator
When writing code you might be tempted to test for Noneness like this:
if value==None:
pass
Or to test for falsehood l...
Show current assembly instruction in GDB
...x │
│0x7ffff740d769 <__libc_start_main+233> callq *0x18(%rsp) │
>│0x7ffff740d76d <__libc_start_main+237> mov %eax,%edi │
│0x7ffff740d76f <__libc_start_main+239> callq 0x7ffff7427970 <exit> ...
How to duplicate sys.stdout to a log file?
...est way to accomplish logging when a python app is making a lot of system calls?
17 Answers
...
How do you debug PHP scripts? [closed]
...r_dump and print at various points to see where your flow goes wrong. When all else fails though and all I have is SSH and vim I still var_dump()/die() to find where the code goes south.
share
...
Proper way to return JSON using node or Express
...n do this by changing the options instead.
'json replacer' JSON replacer callback, null by default
'json spaces' JSON response spaces for formatting, defaults to 2 in development, 0 in production
Not actually recommended to set to 40
app.set('json spaces', 40);
Then you could just respond with so...
How to make a cross-module variable?
...as if a global from any other module that includes __builtin__ -- which is all of them, by default.
a.py contains
print foo
b.py contains
import __builtin__
__builtin__.foo = 1
import a
The result is that "1" is printed.
Edit: The __builtin__ module is available as the local symbol __builtin...
How to implement a good __hash__ function in python [duplicate]
... are equal. It also shouldn't change over the lifetime of the object; generally you only implement it for immutable objects.
A trivial implementation would be to just return 0. This is always correct, but performs badly.
Your solution, returning the hash of a tuple of properties, is good. But note...
Why does this go into an infinite loop?
...
Note: Originally I posted C# code in this answer for purposes of illustration, since C# allows you to pass int parameters by reference with the ref keyword. I've decided to update it with actual legal Java code using the first MutableInt...
What to do Regular expression pattern doesn't match anywhere in string?
...
Contrary to all the answers here, for what you're trying to do regex is a perfectly valid solution. This is because you are NOT trying to match balanced tags-- THAT would be impossible with regex! But you are only matching what's in one ...
Is there a way to access method arguments in Ruby?
... "#{arg} = #{eval arg}" }.join(', ')
Note: since this answer was originally written, in current versions of Ruby eval can no longer be called with a symbol. To address this, an explicit to_s has been added when building the list of parameter names i.e. parameters.map { |arg| arg[1].to_s }
...