大约有 44,000 项符合查询结果（耗时：0.0710秒） [XML]
Should I use string.isEmpty() or “”.equals(string)?
...equals(s) is you don't need the null check (equals will check its argument and return false if it's null), which you seem to not care about. If you're not worried about s being null (or are otherwise checking for it), I would definitely use s.isEmpty(); it shows exactly what you're checking, you ca...
Checking if all elements in a list are unique
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Not the most efficient, but straight forward and concise:
if len(x) > len(set(x)):
pass # do something
Probably won't make much of a difference for short lists.
share
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List all indexes on ElasticSearch server?
...curl http://localhost:9200/_aliases
this will give you a list of indices and their aliases.
If you want it pretty-printed, add pretty=true:
curl http://localhost:9200/_aliases?pretty=true
The result will look something like this, if your indices are called old_deuteronomy and mungojerrie:
{
...
best way to preserve numpy arrays on disk
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h5py example and pytables example
– Kamil Slowikowski
Sep 23 '16 at 13:15
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How to remove all the occurrences of a char in c++ string
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Basically, replace replaces a character with another and '' is not a character. What you're looking for is erase.
See this question which answers the same problem. In your case:
#include <algorithm>
str.erase(std::remove(str.begin(), str.end(), 'a'), str.end());
Or us...
Appending to an existing string
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Indeed - and << is also shorter to write AND looks similar to the C++ cout variant. << is beauty!
– shevy
Aug 19 '16 at 18:24
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Are tuples more efficient than lists in Python?
Is there any performance difference between tuples and lists when it comes to instantiation and retrieval of elements?
8 A...
Value of i for (i == -i && i != 0) to return true in Java
...000000000000000000
Taking the negative value is done by first swapping 0 and 1, which gives
01111111111111111111111111111111
and by adding 1, which gives
10000000000000000000000000000000
As you can see in the link I gave, Wikipedia mentions the problem with the most negative numbers and spec...
What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
Regular expression to match a word or its prefix
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Square brackets are meant for character class, and you're actually trying to match any one of: s, |, s (again), e, a, s (again), o and n.
Use parentheses instead for grouping:
(s|season)
or non-capturing group:
(?:s|season)
Note: Non-capture groups tell the engin...