大约有 40,000 项符合查询结果(耗时:0.0240秒) [XML]

https://stackoverflow.com/ques... 

How can I check for Python version in a program that uses new language features?

...oesn't have ternary Also, with is available in Python 2.5, just add from __future__ import with_statement. EDIT: to get control early enough, you could split it into different .py files and check compatibility in the main file before importing (e.g. in __init__.py in a package): # __init__.py #...
https://stackoverflow.com/ques... 

Portable way to get file size (in bytes) in shell?

... One would guess the portable ls -ln FILE | { read _ _ _ _ size _ && echo "$size"; } needs not fork for the second step of the pipeline, as it uses just built-ins, but Bash 4.2.37 on Linux forks twice (still only one execve, though). – Palec ...
https://stackoverflow.com/ques... 

Can iterators be reset in Python?

...r protocol is very simple, and only provides one single method (.next() or __next__()), and no method to reset an iterator in general. The common pattern is to instead create a new iterator using the same procedure again. If you want to "save off" an iterator so that you can go back to its beginni...
https://stackoverflow.com/ques... 

Test if a variable is a list or tuple

... How about: hasattr(a, "__iter__") ? It tells if the object returned can be iterated over as a generator. By default, tuples and lists can, but not the string types. share...
https://stackoverflow.com/ques... 

How to join strings in Elixir?

...u could treat it as an iolist: ["StringA", " ", "StringB"] |> IO.iodata_to_binary # "StringA StringB" This gives you some performances boosts as you're not duplicating any of the strings in memory. share | ...
https://stackoverflow.com/ques... 

How to simulate target=“_blank” in JavaScript

... <script> window.open('http://www.example.com?ReportID=1', '_blank'); </script> The second parameter is optional and is the name of the target window. share | improve this ans...
https://stackoverflow.com/ques... 

How can we match a^n b^n with Java regex?

... testAll($r, $tests) { foreach ($tests as $test) { $isMatch = preg_match($r, $test, $groups); $groupsJoined = join('|', $groups); print("$test $isMatch $groupsJoined\n"); } } $tests = array('aaa', 'aaab', 'aaaxb', 'xaaab', 'b', 'abbb'); $r1 = '/^a+(?=b+)/'; # └...
https://stackoverflow.com/ques... 

Why does ++[[]][+[]]+[+[]] return the string “10”?

... +(true) + '' + (0) 1 + '' + 0 "10" So now you got that, try this one: _=$=+[],++_+''+$ share | improve this answer | follow | ...
https://stackoverflow.com/ques... 

Convert a PHP object to an associative array

...ect $object = new StdClass; $object->foo = 1; $object->bar = 2; var_dump( (array) $object ); Output: array(2) { 'foo' => int(1) 'bar' => int(2) } Example: Complex Object class Foo { private $foo; protected $bar; public $baz; public function __construct() ...
https://stackoverflow.com/ques... 

How to round a number to significant figures in Python

...t digit: >>> from math import log10, floor >>> def round_to_1(x): ... return round(x, -int(floor(log10(abs(x))))) ... >>> round_to_1(0.0232) 0.02 >>> round_to_1(1234243) 1000000.0 >>> round_to_1(13) 10.0 >>> round_to_1(4) 4.0 >>> rou...