大约有 15,400 项符合查询结果（耗时：0.0240秒） [XML]
Getting the count of unique values in a column in bash
...order of count (highest count first). How would I accomplish this in a Linux command line environment?
5 Answers
...
how do you filter pandas dataframes by multiple columns
...nswered Feb 28 '14 at 4:40
zhangxaochenzhangxaochen
18.6k88 gold badges4444 silver badges6262 bronze badges
...
Why does ~True result in -2?
...differently. They are subclasses of the integer type int.
So they behave exactly as 1 and 0, except that bool redefines str and repr to display them differently.
>>> type(True)
<class 'bool'>
>>> isinstance(True, int)
True
>>> True == 1
True
>>> True is 1...
How to find memory leak in a C++ code/project?
...ed on the heap. If you don't delete it, it will persist after the program exits from the function:
void Leak(int x){
char* p = new char [x];
// delete [] p; // Remove the first comment marking to correct.
}
5
Pay attention to the square braces after "delete." Use delete by itself to free a si...
Time complexity of Sieve of Eratosthenes algorithm
...imes up to n, which is O(n log log n). (See here or here.)
The "find the next prime number" bit is only O(n) overall, amortized — you will move ahead to find the next number only n times in total, not per step. So this whole part of the algorithm takes only O(n).
So using these two you get an u...
Task not serializable: java.io.NotSerializableException when calling function outside closure only o
...
RDDs extend the Serialisable interface, so this is not what's causing your task to fail. Now this doesn't mean that you can serialise an RDD with Spark and avoid NotSerializableException
Spark is a distributed computing engine and...
What's the point of 'meta viewport user-scalable=no' in the Google Maps API
I'm using the Google Maps JavaScript API V3 and the official examples always have you include this meta tag:
4 Answers
...
A proper wrapper for console.log with correct line number?
...seful. This solution works in every browser and reports all console data exactly as it should. No hacks required and one line of code Check out the codepen.
var debug = console.log.bind(window.console)
Create the switch like this:
isDebug = true // toggle this to turn on / off for global contr...
Detecting 'stealth' web-crawlers
...ompany to help them implement a solution to this. The system I developed examined web server logs for excessive activity from any given IP address and issued firewall rules to block offenders. It included whitelists of IP addresses/ranges based on http://www.iplists.com/, which were then updated a...
subtle differences between JavaScript and Lua [closed]
...mparison operators. In JS, only === and !== don't type juggle.
Lua has an exponentiation operator (^); JS doesn't. JS uses different operators, including the ternary conditional operator (?: vs and/or), and, as of 5.3, bitwise operators (&, |, etc. vs. metamethods ).
UPDATE: JS now has the exp...