大约有 32,294 项符合查询结果（耗时：0.0377秒） [XML]
Is there shorthand for returning a default value if None in Python? [duplicate]
...@starhusker's x or "default". Often I used to use the ternary sytax b/c I what to do x.value if X might be None. So x.value if x else "default", but this is more readable getattr(obj, "value", "default"). The trade off is that the later is not caught by many auto-refactor tools.
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JOIN queries vs multiple queries
...ct, if you're not joining tables here and there, you're doing SQL wrong.) What i was talking about is cross joins, which are almost always undesirable even between two tables, let alone 5 -- and which would be about the only way to get the otherwise-totally-bogus "2268000" results mentioned above.
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When to wrap quotes around a shell variable?
...t need quotes since it's a numeric value. Whether $URL needs it depends on what you allow in there and whether you still want an argument if it's empty.
I tend to always quote strings just out of habit since it's safer that way.
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mingw-w64 threads: posix vs win32
...Windows and there are two options: win32 threads and posix threads. I know what is the difference between win32 threads and pthreads but I don't understand what is the difference between these two options. I doubt that if I will choose posix threads it will prevent me from calling WinAPI functions l...
Why are we not to throw these exceptions?
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What might also be somewhat related, NullReferenceException is usually internally thrown as a special case of an AccessViolationException (IIRC the test is something like cmp [addr], addr, ie. it tries to dereference the poin...
How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...cepts various types as inputs. The following are all valid ways of getting what you want:
df['countries'].isin(c1)
0 False
1 True
2 False
3 False
4 True
Name: countries, dtype: bool
# `in` operation
df[df['countries'].isin(c1)]
countries
1 UK
4 China
# `not in` ope...
How to add months to a date in JavaScript? [duplicate]
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@KyleMit Depends on what you expect.
– xehpuk
Sep 7 '17 at 13:58
6
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How to preview git-pull without doing fetch?
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What works for me (after the git fetch): git log origin/master
– slaman
Oct 28 '16 at 18:29
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Still Reachable Leak detected by Valgrind
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can you surmise what the munmap() is doing that makes the "still reachable" blocks disappear?
– user191776
Oct 4 '10 at 18:38
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What are the “standard unambiguous date” formats for string-to-date conversion in R?
...site, mm-dd is not a date (neither is mm-yy or mm-yyyy). You cannot parse what it is not there.
– Dirk Eddelbuettel
May 23 at 18:44
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