大约有 40,000 项符合查询结果（耗时：0.0586秒） [XML]
How can I get nth element from a list?
...
Personally I can't comprehend how an at-index accessor that doesn't return a Maybe type is acceptable as idiomatic Haskell. [1,2,3]!!6 will give you a runtime error. It could very easily be avoided if !! had the type [a] -> Int ...
Can a variable number of arguments be passed to a function?
...able to pass any number of arguments.
def manyArgs(*arg):
print "I was called with", len(arg), "arguments:", arg
>>> manyArgs(1)
I was called with 1 arguments: (1,)
>>> manyArgs(1, 2, 3)
I was called with 3 arguments: (1, 2, 3)
As you can see, Python will unpack the arguments...
Converting strings to floats in a DataFrame
...newer version of pandas (0.17 and up), you can use to_numeric function. It allows you to convert the whole dataframe or just individual columns. It also gives you an ability to select how to treat stuff that can't be converted to numeric values:
import pandas as pd
s = pd.Series(['1.0', '2', -3])
p...
Can I get CONST's defined on a PHP class?
...:class would work fine, but if you'd use those in e.g. namespace Jungle - calling B::class there without including it with use would result in Jungle\B (even though Jungle does NOT have B at all!)
– jave.web
Sep 5 '19 at 18:07
...
Programmatically stop execution of python script? [duplicate]
...
You could raise SystemExit(0) instead of going to all the trouble to import sys; sys.exit(0).
share
|
improve this answer
|
follow
|
...
PHP mkdir: Permission denied problem
...te permissions on the directory.
Here's what you do in Ubuntu
Make sure all files are owned by the Apache group and user. In Ubuntu it is the www-data group and user
chown -R www-data:www-data /path/to/webserver/www
Next enabled all members of the www-data group to read and write files
chmod -R...
What is the copy-and-swap idiom?
...s arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided?
The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee.
How does it wor...
What characters are valid for JavaScript variable names?
...ou an idea of how wrong Anthony Mills' answer is: if you were to summarize all these rules in a single ASCII-only regular expression for JavaScript, it would be 11,236 characters long. Here it is:
// ES5.1 / Unicode 6.1
/^(?!(?:do|if|in|for|let|new|try|var|case|else|enum|eval|false|null|this|true|v...
Redirect all to index.php using htaccess
...le PHP-based MVC-ish framework. I want this framework to be able to be installed in any directory.
7 Answers
...
How do I pass JavaScript variables to PHP?
...
@sergey, so i need to use ajax? Actually, i'm familliar with that.
– SUN Jiangong
Dec 18 '09 at 10:08
...