大约有 40,000 项符合查询结果（耗时：0.0427秒） [XML]
Check whether a path is valid in Python without creating a file at the path's target
...
I need to test if the file-name is a valid, e.g. if the file-system will allow me to create a file with such a name.
The file-name has some unicode characters in it.
...
Why use Abstract Base Classes in Python?
...emented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a s...
PostgreSQL create table if not exists
...
CREATE TABLE myschema.mytable (i integer);
END IF;
END
$func$;
Call:
SELECT create_mytable(); -- call as many times as you want.
Notes:
The columns schemaname and tablename in pg_tables are case-sensitive. If you double-quote identifiers in the CREATE TABLE statement, you need ...
How to compare two colors for similarity/difference
...d with what percentage. The thing is that I don't know how to do that manually step by step. So it is even more difficult to think of a program.
...
How to properly add include directories with CMake
...the headers... Do I need to list the headers of just this library, or also all the headers that it might depend on (on top of declaring the dependency on the library) ? It's a growing project and I quite dread the idea of adding a header to all the dependencies when I add one in the root library.
...
How to backup a local Git repository?
I am using git on a relatively small project and I find that zipping the .git directory's contents might be a fine way to back up the project. But this is kind of weird because, when I restore, the first thing I need to do is git reset --hard .
...
MySQL search and replace some text in a field
... @inemanja, @Air without the WHERE clause you do an UPDATE on all the rows...
– Alexis Wilke
Jun 25 '15 at 3:37
7
...
What is an 'endpoint' in Flask?
...erkzeug library) is to map URL paths to some logic that you will run (typically, the "view function"). Your basic view is defined like this:
@app.route('/greeting/<name>')
def give_greeting(name):
return 'Hello, {0}!'.format(name)
Note that the function you referred to (add_url_rule) ac...
Dynamic variable names in Bash
...Fgilrtux] [-p] [name[=value] ...]. You might double-check that you are actually running 4.x and not 3.2.
– chepner
Dec 2 '13 at 16:08
5
...
How to enter a multi-line command
...me
However, this is only ever necessary in such cases as shown above. Usually you get automatic line continuation when a command cannot syntactically be complete at that point. This includes starting a new pipeline element:
Get-ChildItem |
Select Name,Length
will work without problems since a...