大约有 46,000 项符合查询结果（耗时：0.0319秒） [XML]
Regex Named Groups in Java
It is my understanding that the java.regex package does not have support for named groups ( http://www.regular-expressions.info/named.html ) so can anyone point me towards a third-party library that does?
...
Checking if a string can be converted to float in Python
.....
try:
float(element)
except ValueError:
print "Not a float"
..it's simple, and it works
Another option would be a regular expression:
import re
if re.match(r'^-?\d+(?:\.\d+)?$', element) is None:
print "Not float"
...
VS Debug调试模式下内存泄露检测原理 - C/C++ - 清泛网 - 专注C/C++及内核技术
...T宏定义了malloc、realloc，如下：
#define malloc(s) _malloc_dbg(s, _NORMAL_BLOCK, __FILE__, __LINE__)
#define calloc(c, s) _calloc_dbg(c, s, _NORMAL_BLOCK, __FILE__, __LINE__)
#define realloc(p, s) _realloc_dbg(p, s, _NORMAL_BLOCK, __FILE__, __LINE__)
...
Is “argv[0] = name-of-executable” an accepted standard or just a common convention?
...r if the program name is not available from the host environment.
So no, it's only the program name if that name is available. And it "represents" the program name, not necessarily is the program name. The section before that states:
If the value of argc is greater than zero, the array members...
Mediator Vs Observer Object-Oriented Design Patterns
...many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
The Mediator pattern:
Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other...
Oracle “(+)” Operator
...table references) didn't standardize OUTER joins.
The query would be re-written in ANSI-92 syntax as:
SELECT ...
FROM a
LEFT JOIN b ON b.id = a.id
This link is pretty good at explaining the difference between JOINs.
It should also be noted that even though the (+) works, Oracle recomm...
Why is SQL Server 2008 Management Studio Intellisense not working?
I'm being driven to insanity trying to figure out why Intellisense just fails to work at all. The server I'm using is local and is 2008, the database is set to 2008 compatibility, Intellisense is on in every menu I can find, and yet no member list will pop up even with a CTRL-J.
...
Flatten nested dictionaries, compressing keys
...ay you would flatten a nested list, you just have to do the extra work for iterating the dict by key/value, creating new keys for your new dictionary and creating the dictionary at final step.
import collections
def flatten(d, parent_key='', sep='_'):
items = []
for k, v in d.items():
...
c++ 写日志通用类，可设置日志级别 - C/C++ - 清泛网 - 专注C/C++及内核技术
...。代码经过较长时间的测试，可用性高。Logger.h
#ifndef __LOGGER_H_
#define __LOGGER_H_
#include <iostream>
#include <atlstr.h>
#pragma warning(disable:4996)
#define LEVEL_FATAL 0
#define LEVEL_ERROR 1
#define LEVEL_WARN 2
#define LEVEL_INFO 3
#define LEVEL_VERBOSE...
Logical operators for boolean indexing in Pandas
I'm working with boolean index in Pandas.
The question is why the statement:
3 Answers
...