大约有 44,300 项符合查询结果（耗时：0.0431秒） [XML]
append multiple values for one key in a dictionary [duplicate]
...
209
If I can rephrase your question, what you want is a dictionary with the years as keys and an a...
How do you get the width and height of a multi-dimensional array?
...
247
You use Array.GetLength with the index of the dimension you wish to retrieve.
...
How do I determine the target architecture of static library (.a) on Mac OS X?
...
244
Another option is lipo; its output is brief and more readable than otool's.
An example:
% li...
Insert, on duplicate update in PostgreSQL?
...ing syntax (similar to MySQL)
INSERT INTO the_table (id, column_1, column_2)
VALUES (1, 'A', 'X'), (2, 'B', 'Y'), (3, 'C', 'Z')
ON CONFLICT (id) DO UPDATE
SET column_1 = excluded.column_1,
column_2 = excluded.column_2;
Searching postgresql's email group archives for "upsert" leads to...
How to secure MongoDB with username and password
...
120
You need to start mongod with the --auth option after setting up the user.
From the MongoDB Si...
Painless way to install a new version of R?
... |
edited May 8 '19 at 2:46
Gregor Thomas
91.9k1515 gold badges126126 silver badges235235 bronze badges
...
Why does Python print unicode characters when the default encoding is ASCII?
From the Python 2.6 shell:
6 Answers
6
...
How does Python manage int and long?
...
126
int and long were "unified" a few versions back. Before that it was possible to overflow an int...
Are GUID collisions possible?
I'm working on a database in SQL Server 2000 that uses a GUID for each user that uses the app it's tied to. Somehow, two users ended up with the same GUID. I know that microsoft uses an algorithm to generate a random GUID that has an extremely low chance of causing collisons, but is a collision stil...
What is the fastest or most elegant way to compute a set difference using Javascript arrays?
...if don't know if this is most effective, but perhaps the shortest
A = [1, 2, 3, 4];
B = [1, 3, 4, 7];
diff = A.filter(function(x) { return B.indexOf(x) < 0 })
console.log(diff);
Updated to ES6:
A = [1, 2, 3, 4];
B = [1, 3, 4, 7];
diff = A.filter(x => !B.includes(x) );
console.log(diff)...