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Makefile经典教程（入门必备） - C/C++ - 清泛网移动版 - 专注C/C++及内核技术
...e中有这些功能，一是很实用，二是可以显得你的makefile很专业（不是那种初学者的作品）。
四、检查规则
有时候，我们不想让我们的makefile中的规则执行起来，我们只想检查一下我们的命令，或是执行的序列。于是我们...
Regular expression that matches valid IPv6 addresses
I'm having trouble writing a regular expression that matches valid IPv6 addresses, including those in their compressed form (with :: or leading zeros omitted from each byte pair).
...
What are the differences between json and simplejson Python modules?
...
json is simplejson, added to the stdlib. But since json was added in 2.6, simplejson has the advantage of working on more Python versions (2.4+).
simplejson is also updated more frequently than Python, so if you need (or want) the latest version, it's best to use simplejson itself, if possible...
Pandas index column title or name
... JeffJeff
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10
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How to select rows from a DataFrame based on column values?
... 0 0
# 1 bar one 1 2
# 2 foo two 2 4
# 3 bar three 3 6
# 4 foo two 4 8
# 5 bar two 5 10
# 6 foo one 6 12
# 7 foo three 7 14
print(df.loc[df['A'] == 'foo'])
yields
A B C D
0 foo one 0 0
2 foo two 2 4
4 foo two 4 8
6 f...
What is the difference between Ruby 1.8 and Ruby 1.9
... character strings.
Ruby 1.9
irb(main):001:0> ?c
=> "c"
Ruby 1.8.6
irb(main):001:0> ?c
=> 99
String index.
Ruby 1.9
irb(main):001:0> "cat"[1]
=> "a"
Ruby 1.8.6
irb(main):001:0> "cat"[1]
=> 97
{"a","b"} No Longer Supported
Ruby 1.9
irb(main):002:0> {1,2}...
How to find list intersection?
actual output: [1,3,5,6]
expected output: [1,3,5]
11 Answers
11
...
What is the ultimate postal code and zip regex?
...still be missing on the validation part: Zip code 12345 may exist, but 12346 not, maybe 12344 doesn't exist either. How do you check for that with a regex?
You can't.
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...
Difference between numpy.array shape (R, 1) and (R,)
...
6 Answers
6
Active
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pandas: filter rows of DataFrame with operator chaining
..." filtering is done by "chaining" the criteria in the boolean index.
In [96]: df
Out[96]:
A B C D
a 1 4 9 1
b 4 5 0 2
c 5 5 1 0
d 1 3 9 6
In [99]: df[(df.A == 1) & (df.D == 6)]
Out[99]:
A B C D
d 1 3 9 6
If you want to chain methods, you can add your own mask ...