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正则表达式 30 分钟入门教程 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...输入的内容时非常有用，比如一个网站如果要求你填写的QQ号必须为5位到12位数字时，可以使用：^\d{5,12}$。
这里的{5,12}和前面介绍过的{2}是类似的，只不过{2}匹配只能不多不少重复2次，{5,12}则是重复的次数不能少于5次，不能...
How to write UPDATE SQL with Table alias in SQL Server 2008?
I have a very basic UPDATE SQL -
2 Answers
2
...
What is the difference between a pseudo-class and a pseudo-element in CSS?
...nsists of a "colon" (:) followed by the name of the pseudo-class and optionally by a value between parentheses.
Pseudo-classes are allowed in all sequences of simple selectors contained in a selector. Pseudo-classes are allowed anywhere in sequences of simple selectors, after the leading type s...
How to find if directory exists in Python
...e is_dir() and exists() methods of a Path object can be used to answer the question:
In [1]: from pathlib import Path
In [2]: p = Path('/usr')
In [3]: p.exists()
Out[3]: True
In [4]: p.is_dir()
Out[4]: True
Paths (and strings) can be joined together with the / operator:
In [5]: q = p / 'bin' ...
How can I get the Google cache age of any URL or web page? [closed]
...
Use the URL
https://webcache.googleusercontent.com/search?q=cache:<your url without "http://">
Example:
https://webcache.googleusercontent.com/search?q=cache:stackoverflow.com
It contains a header like this:
This is Google's cache of https://stackoverflow.com/. It ...
How can I use a search engine to search for special characters? [closed]
...
symbolhound.com/?q=???? <- does not work. Great project though! =)
– HyderA
Feb 1 '12 at 7:24
8
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Python: how to print range a-z?
...k l m n
>>> print(" ".join(small_letters[0::2]))
a c e g i k m o q s u w y
>>> s = small_letters[0:(ord('n')-ord('a')+1):2]
>>> print(" ".join(s))
a c e g i k m
>>> urls = ["hello.com/", "hej.com/", "hallo.com/"]
>>> print([x + y for x, y in zip(urls, ...
How to view method information in Android Studio?
...X, Android Studio > Preferences > Editor > General and check Show quick documentation on mouse move:
Other ways:
You can go into your IntelliJ's bin folder and search for idea.properties. Add this line to the document:
auto.show.quick.doc=true
Now you'll have the same floating docs w...
What is tail recursion?
...return x;
} else {
return x + recsum(x - 1);
}
}
If you called recsum(5), this is what the JavaScript interpreter would evaluate:
recsum(5)
5 + recsum(4)
5 + (4 + recsum(3))
5 + (4 + (3 + recsum(2)))
5 + (4 + (3 + (2 + recsum(1))))
5 + (4 + (3 + (2 + 1)))
15
Note how every recur...
Use a URL to link to a Google map with a marker on it
... can use the following URL:
https://www.google.com/maps/search/?api=1&query=36.26577,-92.54324
For further details please read aforementioned documentation.
You can also file feature requests for this API in Google issue tracker.
Hope this helps!
...