大约有 15,000 项符合查询结果（耗时：0.0260秒） [XML]
Which is faster: Stack allocation or Heap allocation
...ck it would give you a Stack Overflow. Try for example in C++ this: int t[100000000]; Try for example t[10000000] = 10; and then cout << t[10000000]; It should give you a stack overflow or just won't work and won't show you anything. But if you allocate the array on the heap: int *t = new int[...
Ruby, remove last N characters from a string?
... 1.874237 0.001472 1.875709 ( 1.876820)
delete_suffix 0.721699 0.000945 0.722644 ( 0.723410)
delete_suffix! 0.650042 0.000714 0.650756 ( 0.651332)
I hope this is useful - note the method doesn't currently accept a regex so if you don't know the suffix it's not viable for the ti...
ERROR 2003 (HY000): Can't connect to MySQL server on '127.0.0.1' (111)
I use the following command:
15 Answers
15
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Check if a given key already exists in a dictionary
...est you can run yourself. The results may astonish you. For dicts with ~50,000 keys, not calling keys() gives you .01 second computational benefit. For ~500,000 keys, not calling keys() gives you .1 second benefit. For ~5,000,000 keys, not calling keys() is .4 seconds faster, but for 50,000,000 keys...
Does JavaScript have a built in stringbuilder class?
...script-concat-vs-join/2.
The test-cases concatenate or join the alphabet 1,000 times.
In current browsers (FF, Opera, IE11, Chrome), "concat" is about 4-10 times faster than "join".
In IE8, both return about equal results.
In IE7, "join" is about 100 times faster unfortunately.
...
ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage? [closed]
...
We use Sphinx in a Vertical Search project with 10.000.000 + of MySql records and 10+ different database .
It has got very excellent support for MySQL and high performance on indexing , research is fast but maybe a little less than Lucene.
However it's the right choice if you...
How to convert a string to an integer in JavaScript?
...simplest way would be to use the native Number function:
var x = Number("1000")
If that doesn't work for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods.
parseInt:
var x = parseInt("1000", 10); // you want to use radix 10
// so you get a decimal n...
How to check if a number is a power of 2
... 0 = 0, 0 & 0 = 0, and 0 & 1 = 0. So we do the math:
100
011
----
000
The result is simply 0. So we go back and look at what our return statement now translates to:
return (4 != 0) && ((4 & 3) == 0);
Which translates now to:
return true && (0 == 0);
return true...
Getting unique items from a list [duplicate]
...such as a Dictionary or HashSet. Because currently, if source contains 100,000 items with many duplicates, then in every one of the 100,000 iterations you will be scanning a list on the order of 100,000 items, meaning you are scanning on the order of 100,000 * 100,000 items. Quadratic time complexit...
How to test if a string is basically an integer in quotes using Ruby
...es when parsing integers (negative numbers, hex, octal, underscores e.g. 1_000_000) it would be a very big Regex and easy to get wrong. Integer() is canonical because with Integer ()you know for sure that anything that Ruby considers an integer literal will be accepted, and everything else will be ...