大约有 40,900 项符合查询结果（耗时：0.0405秒） [XML]
How to run multiple Python versions on Windows
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136
Running a different copy of Python is as easy as starting the correct executable. You mention t...
How do I check if a string is unicode or ascii?
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301
In Python 3, all strings are sequences of Unicode characters. There is a bytes type that holds...
How to insert newline in string literal?
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323
Well, simple options are:
string.Format:
string x = string.Format("first line{0}second line...
Pandas dataframe get first row of each group
...;> df.groupby('id').first()
value
id
1 first
2 first
3 first
4 second
5 first
6 first
7 fourth
If you need id as column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6...
Uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)
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137
This is an incompatibility between Rails 2.3.8 and recent versions of RubyGems. Upgrade to the ...
What is the smallest possible valid PDF?
...lt;/Type/Catalog/Pages 2 0 R>>endobj 2 0 obj<</Type/Pages/Kids[3 0 R]/Count 1>>endobj 3 0 obj<</Type/Page/MediaBox[0 0 3 3]>>endobj
xref
0 4
0000000000 65535 f
0000000010 00000 n
0000000053 00000 n
0000000102 00000 n
trailer<</Size 4/Root 1 0 R>>
startxref
1...
Joda-Time: what's the difference between Period, Interval and Duration?
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3 classes are needed because they represent different concepts so it is a matter of picking the appropriate one for the job rather than of relative performance. From the documentation with comments added by me in italics:
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Python, compute list difference
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373
If the order does not matter, you can simply calculate the set difference:
>>> set([...
Python assigning multiple variables to same value? list behavior
...es are naming the same object, use the is operator:
>>> a=b=c=[0,3,5]
>>> a is b
True
You then ask:
what is different from this?
d=e=f=3
e=4
print('f:',f)
print('e:',e)
Here, you're rebinding the name e to the value 4. That doesn't affect the names d and f in any way.
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