大约有 42,000 项符合查询结果（耗时：0.0333秒） [XML]
Should I use a data.frame or a matrix?
When should one use a data.frame , and when is it better to use a matrix ?
6 Answers
...
Why does appending “” to a String save memory?
I used a variable with a lot of data in it, say String data .
I wanted to use a small part of this string in the following way:
...
Why is semicolon allowed in this python snippet?
Python does not warrant the use of semicolons to end statements.
So why is this (below) allowed?
15 Answers
...
Grabbing the href attribute of an A element
Trying to find the links on a page.
10 Answers
10
...
When should I use a struct rather than a class in C#?
When should you use struct and not class in C#? My conceptual model is that structs are used in times when the item is merely a collection of value types . A way to logically hold them all together into a cohesive whole.
...
Check if a Class Object is subclass of another Class Object in Java
I'm playing around with Java's reflection API and trying to handle some fields. Now I'm stuck with identifying the type of my fields. Strings are easy, just do myField.getType().equals(String.class) . The same applies for other non-derived classes. But how do I check derived classes? E.g. LinkedLi...
How to modify list entries during for loop?
Now I know that it is not safe to modify the list during an iterative looping. However, suppose I have a list of strings, and I want to strip the strings themselves. Does replacement of mutable values count as modification?
...
Are duplicate keys allowed in the definition of binary search trees?
I'm trying to find the definition of a binary search tree and I keep finding different definitions everywhere.
12 Answers
...
What are the differences between B trees and B+ trees?
In a b-tree you can store both keys and data in the internal and leaf nodes , but in a b+ tree you have to store the data in the leaf nodes only .
...
What's this =! operator? [duplicate]
I was surprised by this code:
13 Answers
13
...