大约有 40,000 项符合查询结果（耗时：0.0521秒） [XML]
Can I install Python windows packages into virtualenvs?
Virtualenv is great: it lets me keep a number of distinct Python installations so that different projects' dependencies aren't all thrown together into a common pile.
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How assignment works with Python list slice?
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To be clear, "takes a slice of" really means "make a copy of a slice of" which is where part of the confusion comes from.
– Mark Ransom
May 16 '12 at 17:12
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Why does += behave unexpectedly on lists?
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The general answer is that += tries to call the __iadd__ special method, and if that isn't available it tries to use __add__ instead. So the issue is with the difference between these special methods.
The __iadd__ special method is for an in-place addition, that i...
What is the volatile keyword useful for?
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volatile has semantics for memory visibility. Basically, the value of a volatile field becomes visible to all readers (other threads in particular) after a write operation completes on it. Without volatile, readers could see some non-updated value.
To answer your question: Y...
Principles for Modeling CouchDB Documents
...or instance). Managing the relationships or connections between various, smaller documents can be confusing at first, but CouchDB provides several options for combining disparate pieces into single responses.
The first big one is view collation. When you emit key/value pairs into the results of a m...
SQL Add foreign key to existing column
...sed an error trying to create the relationships to the other table. Thanks all.
– ExceptionLimeCat
Apr 30 '12 at 20:35
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Understanding scala enumerations
...er Value representing the individual elements of the enumeration (it's actually an inner class, but the difference doesn't matter here).
Thus object WeekDay inherits that type member. The line type WeekDay = Value is just a type alias. It is useful, because after you import it elsewhere with import...
Node.js get file extension
... Try 'filename.css.gz'.split('.').slice(1).join('.') to get all extensions
– Trevor
Jul 31 '17 at 21:53
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How to parse/read a YAML file into a Python object? [duplicate]
...ame: Node 2
branch2-1:
name: Node 2-1
And you've installed PyYAML like this:
pip install PyYAML
And the Python code looks like this:
import yaml
with open('tree.yaml') as f:
# use safe_load instead load
dataMap = yaml.safe_load(f)
The variable dataMap now contains...
How to do what head, tail, more, less, sed do in Powershell? [closed]
...an above option
gc log.txt | more # or less if you have it installed
gc log.txt | %{ $_ -replace '\d+', '($0)' } # sed
This works well enough for small files, larger ones (more than a few MiB) are probably a bit slow.
The PowerShell Community Extensions include some cmdlets fo...