大约有 40,000 项符合查询结果(耗时:0.0485秒) [XML]

https://stackoverflow.com/ques... 

Why is iterating through a large Django QuerySet consuming massive amounts of memory?

...rst time you iterate over it. For example, this will print the headline of all entries in the database: for e in Entry.objects.all(): print e.headline So your ten million rows are retrieved, all at once, when you first enter that loop and get the iterating form of the queryset. The wait ...
https://stackoverflow.com/ques... 

Standardize data columns in R

I have a dataset called spam which contains 58 columns and approximately 3500 rows of data related to spam messages. 15 ...
https://stackoverflow.com/ques... 

Can I get Memcached running on a Windows (x64) 64bit environment?

...wnload. Now they have made it part of their commercial No-SQL DB offering called Membase. It can be configured to run in Memcached-only mode (i.e. without persistence) and there's a 100% free version too. Check it out here: http://www.membase.org/downloads UPDATE 3: MemBase has slept with CouchDB a...
https://stackoverflow.com/ques... 

In Python, when should I use a function instead of a method?

...sulation which is so dear to OO design. The encapsulation principal is really what this comes down to: as a designer you should hide everything about the implementation and class internals which it is not absolutely necessarily for any user or other developer to access. Because we deal with instan...
https://stackoverflow.com/ques... 

Only read selected columns

...g","Sep","Oct","Nov","Dec")) dat <- fread("data.txt", drop = c(8:13)) All result in: > data Year Jan Feb Mar Apr May Jun 1 2009 -41 -27 -25 -31 -31 -39 2 2010 -41 -27 -25 -31 -31 -39 3 2011 -21 -27 -2 -6 -10 -32 UPDATE: When you don't want fread to return a data.table, use the data.ta...
https://stackoverflow.com/ques... 

ios app maximum memory budget

...ered your own question: try not to go beyond the 70 Mb limit, however it really depends on many things: what iOS version you're using (not SDK), how many applications running in background, what exact memory you're using etc. Just avoid the instant memory splashes (e.g. you're using 40 Mb of RAM, a...
https://stackoverflow.com/ques... 

Do I need dependency injection in NodeJS, or how to deal with …?

...eaddirSync method or you can return an entirely different module when you call require. Method 1: var oldmethod = fs.readdirSync; fs.readdirSync = function(dir) { return ['somefile.txt', 'error.txt', 'anotherfile.txt']; }; *** PERFORM TEST *** *** RESTORE METHOD AFTER TEST **** fs.readddirS...
https://stackoverflow.com/ques... 

How to avoid 'cannot read property of undefined' errors?

... Catching all exceptions without re-throwing is bad, and generally using exceptions as part of the expected flow of execution is also not great -- even though in this case it's pretty well contained. – hugo ...
https://stackoverflow.com/ques... 

How to find if a native DLL file is compiled as x64 or x86?

... You can use DUMPBIN too. Use the /headers or /all flag and its the first file header listed. dumpbin /headers cv210.dll 64-bit Microsoft (R) COFF/PE Dumper Version 10.00.30319.01 Copyright (C) Microsoft Corporation. All rights reserved. Dump of file cv210.dll PE ...
https://stackoverflow.com/ques... 

How much is the overhead of smart pointers compared to normal pointers in C++?

..._ptr always has memory overhead for reference counter, though it is very small. std::unique_ptr has time overhead only during constructor (if it has to copy the provided deleter and/or null-initialize the pointer) and during destructor (to destroy the owned object). std::shared_ptr has time overhe...