大约有 46,000 项符合查询结果（耗时：0.0350秒） [XML]
Does Python support short-circuiting?
Does Python support short-circuiting in boolean expressions?
3 Answers
3
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Does use of final keyword in Java improve the performance?
In Java we see lots of places where the final keyword can be used but its use is uncommon.
13 Answers
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Truncating all tables in a Postgres database
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FrustratedWithFormsDesigner is correct, PL/pgSQL can do this. Here's the script:
CREATE OR REPLACE FUNCTION truncate_tables(username IN VARCHAR) RETURNS void AS $$
DECLARE
statements CURSOR FOR
SELECT tablename FROM pg_tabl...
Setting PayPal return URL and making it auto return?
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You have to enable auto return in your PayPal account, otherwise it will ignore the return field.
From the documentation (updated to reflect new layout Jan 2019):
Auto Return is turned off by default.
To turn on Auto Return:
Log in to your PayPal account at https://www.paypa...
Determine project root from a running node.js application
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There are several ways to approach this, each with their own pros and cons:
require.main.filename
From http://nodejs.org/api/modules.html:
When a file is run directly from Node, require.main is set to its module. That means that you can determine whether a file has ...
Serializing object that contains cyclic object value
...cycle or this (simpler) function which just replaces recursive references with nulls:
function decycle(obj, stack = []) {
if (!obj || typeof obj !== 'object')
return obj;
if (stack.includes(obj))
return null;
let s = stack.concat([obj]);
return Ar...
Create a “with” block on several context managers? [duplicate]
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In Python 2.7 and 3.1 and above, you can write:
with A() as X, B() as Y, C() as Z:
do_something()
This is normally the best method to use, but if you have an unknown-length list of context managers you'll need one of the below methods.
In Python 3.3, you can...
multiprocessing: sharing a large read-only object between processes?
...ependent memory space.
Solution 1
To make best use of a large structure with lots of workers, do this.
Write each worker as a "filter" – reads intermediate results from stdin, does work, writes intermediate results on stdout.
Connect all the workers as a pipeline:
process1 <source | proces...
UTF-8: General? Bin? Unicode?
...r various types of data. 100% of the content I will be storing is user-submitted.
5 Answers
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How to read a file into a variable in shell?
I want to read a file and save it in variable, but I need to keep the variable and not just print out the file.
How can I do this? I have written this script but it isn't quite what I needed:
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