大约有 40,000 项符合查询结果（耗时：0.0943秒） [XML]
return, return None, and no return at all?
...
On the actual behavior, there is no difference. They all return None and that's it. However, there is a time and place for all of these.
The following instructions are basically how the different methods should be used (or at least how I was taught they should be used), but th...
Emacs: print key binding for a command or list all key bindings
...a command.
You are correct, C-h b (or M-x describe-bindings) will show you all bindings. C-h m (M-x describe-mode) is also handy to list bindings by mode.
You might also try C-h k (M-x describe-key) to show what command is bound to a key. For instance, on my machine save-buffers-kill-emacs isn't b...
What's the Android ADB shell “dumpsys” tool and what are its benefits?
...r the full list of ADB shell dumpsys commands with a full explanation of all of the commands.
4 Answers
...
Convert list of dictionaries to a pandas DataFrame
...n the structure and format of your data, there are situations where either all three methods work, or some work better than others, or some don't work at all.
Consider a very contrived example.
np.random.seed(0)
data = pd.DataFrame(
np.random.choice(10, (3, 4)), columns=list('ABCD')).to_dict('r...
Delete empty lines using sed
... spaces or tabs in your "empty" line. Use POSIX classes with sed to remove all lines containing only whitespace:
sed '/^[[:space:]]*$/d'
A shorter version that uses ERE, for example with gnu sed:
sed -r '/^\s*$/d'
(Note that sed does NOT support PCRE.)
...
How to search all loaded scripts in Chrome Developer Tools?
In Firebug, you can search some text and it will look for it in all scripts loaded on a page. Can the same be done in Chrome Developer tools while debugging client script? I tried it, but it seems to search only in the script I have open, and not the rest that are on the page.
...
Cross-browser testing: All major browsers on ONE machine
...ri
Adobe Flash Player
Download summary
Sandboxie
Part 2: Installation and configuration
Internet Explorer
Firefox
Opera
Chrome
Safari
Developer tools (and shortcuts)
Measured set-up time and disk space
Time needed per browser (install & config)
Optimal us...
What does {0} mean when initializing an object?
...
What's happening here is called aggregate initialization. Here is the (abbreviated) definition of an aggregate from section 8.5.1 of the ISO spec:
An aggregate is an array or a class with no user-declared constructors, no private or protected non...
How do you delete all text above a certain line
How do you delete all text above a certain line. For deletion below a line I use "d shift g"
5 Answers
...
How do I get SUM function in MySQL to return '0' if no values are found?
...iddle.com/#!2/d1542/3/0
More Information:
Given three tables (one with all numbers, one with all nulls, and one with a mixture):
SQL Fiddle
MySQL 5.5.32 Schema Setup:
CREATE TABLE foo
(
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
val INT
);
INSERT INTO foo (val) VALUES
(null),(1),(n...