大约有 40,000 项符合查询结果（耗时：0.0372秒） [XML]
Flattening a shallow list in Python [duplicate]
...st of iterables with a list comprehension, or failing that, what would you all consider to be the best way to flatten a shallow list like this, balancing performance and readability?
...
TypeError: method() takes 1 positional argument but 2 were given
...- it's just that the first one is implicit, from the point of view of the caller.
This is because most methods do some work with the object they're called on, so there needs to be some way for that object to be referred to inside the method. By convention, this first argument is called self inside ...
What is the X-REQUEST-ID http header?
...ates. If a client receives an error it can include the ID in a bug report, allowing the server operator to look up the corresponding log statements (without having to rely on timestamps, IPs, etc).
As this ID is generated (randomly) by the client it does not contain any sensitive information, and s...
Rails migrations: self.up and self.down versus change
... For example, in your case what is the reverse operation of add_column to call when you rollback? Of course it's remove_column. What is the inverse of create_table? It's drop_table. So in these cases rails know how to rollback and define a down method is superfluous (you can see in the documentation...
How to hide databases that I am not allowed to access
... I connect to my Heroku - Postgresql database via pgAdmin3 , It lists all the tables (about 2600). Every time I open the pgAdmin3 I have to find my own database.
...
Get name of current script in Python
...hen used in the main module, this is the name of the script that was originally invoked.
If you want to omit the directory part (which might be present), you can use os.path.basename(__file__).
share
|
...
PostgreSQL: Is it better to use multiple databases with one schema each, or one database with multip
... the same as a MySQL "database". Having many databases on a PostgreSQL installation can get problematic; having many schemas will work with no trouble. So you definitely want to go with one database and multiple schemas within that database.
...
Rails: Default sort order for a rails model?
...ow use Book.published.confirmed.
With this method, the query is not actually executed until actual results are needed (lazy evaluation), so 7 scopes could be chained together but only resulting in 1 actual database query, to avoid performance problems from executing 7 separate queries.
You can u...
Automatic prune with Git fetch or pull
... work is over and I don't know, I won't do a git fetch --prune and eventually I will push back the deleted branch.
3 Answ...
About Python's built in sort() method
...mergesort that's still used in Java, and one can hope that Java will eventually switch to his recent port of timsort).
Some explanation of the Java port of timsort is here, the diff is here (with pointers to all needed files), the key file is here -- FWIW, while I'm a better C programmer than Java ...