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Multiple levels of 'collection.defaultdict' in Python
...ng specific that you need help with? When d[new_key] is accessed, it will call the lambda which will create a new defaultdict(int). And when d[existing_key][new_key2] is accessed, a new int will be created.
– interjay
Oct 11 '13 at 12:53
...
Is it intended by the C++ standards committee that in C++11 unordered_map destroys what it inserts?
... always move from its argument. It's supposed to move if the argument is really an rvalue, and copy if it's an lvalue.
The behaviour, you observe, which always moves, is a bug in libstdc++, which is now fixed according to a comment on the question. For those curious, I took a look at the g++-4.8 he...
Django database query: How to get object by id?
Django automatically creates an id field as primary key.
6 Answers
6
...
How to print without newline or space?
...to the end of the string:
print('.', end='')
To not add a space between all the function arguments you want to print:
print('a', 'b', 'c', sep='')
You can pass any string to either parameter, and you can use both parameters at the same time.
If you are having trouble with buffering, you can f...
Try catch statements in C
... exceptions but you can simulate them to a degree with setjmp and longjmp calls.
static jmp_buf s_jumpBuffer;
void Example() {
if (setjmp(s_jumpBuffer)) {
// The longjmp was executed and returned control here
printf("Exception happened here\n");
} else {
// Normal code execution s...
ASP.NET Identity's default Password Hasher - How does it work and is it secure?
...ff using decimal numbers is A LOT more intuitive (we have 10 fingers after all - at least most of us), so declaring a number of something using hexadecimals seems like an unnecessary code obfuscation.
– Andrew Cyrul
Apr 13 '17 at 9:27
...
Extract traceback info from an exception object
...ion("foo occurred").with_traceback(tracebackobj)
These features are minimally described as part of the raise documentation.
All credit for this part of the answer should go to Vyctor, who first posted this information. I'm including it here only because this answer is stuck at the top, and Python...
Is there a benefit to defining a class inside another class in Python?
What I'm talking about here are nested classes. Essentially, I have two classes that I'm modeling. A DownloadManager class and a DownloadThread class. The obvious OOP concept here is composition. However, composition doesn't necessarily mean nesting, right?
...
REDHAT 6.4 X64下ORACLE 11GR2静默安装 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...可能会报目录不存在的错误，无视
[root@redhat ~]#yum clean all
[root@redhat ~]#yum makecache
检查一下成功没有
[root@redhat mnt]# yum grouplist
6、安装支持包
[root@redhat yum.repos.d]# cd /mnt/
[root@redhat mnt]# cat pacakage.txt
[root@redhat mnt]# yum install $(...
jumpserver-华为云免费堡垒机解决方案 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...d/bak/
wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
yum clean all
yum makecache
如果是REHL需要修改
1.删除redhat原有的yum
rpm -aq|grep yum|xargs rpm -e --nodeps
2.下载yum安装文件
wget http://mirrors.163.com/centos/6.7/os/x86_64/Packages/yum-3.2.29-69.el6.ce...