大约有 45,000 项符合查询结果（耗时：0.0483秒） [XML]
Best practices for large solutions in Visual Studio (2008) [closed]
...
12 Answers
12
Active
...
MySQL Conditional Insert
...sert, try:
INSERT INTO x_table(instance, user, item)
SELECT 919191, 123, 456
FROM dual
WHERE NOT EXISTS (SELECT * FROM x_table
WHERE user = 123
AND item = 456)
In this, dual is a table with one row only (found origi...
How do I convert a numpy array to (and display) an image?
...
240
You could use PIL to create (and display) an image:
from PIL import Image
import numpy as np
...
Should I use single or double colon notation for pseudo-elements?
...
Do not use both combined with a comma. A CSS 2.1 compliant (not CSS3 capable) user agent will ignore the whole rule:
When a user agent cannot parse the selector (i.e., it is not valid CSS 2.1), it must ignore the selector and the following declaration block (if any)...
How to draw polygons on an HTML5 canvas?
...e a path with moveTo and lineTo (live demo):
var ctx = canvas.getContext('2d');
ctx.fillStyle = '#f00';
ctx.beginPath();
ctx.moveTo(0, 0);
ctx.lineTo(100,50);
ctx.lineTo(50, 100);
ctx.lineTo(0, 90);
ctx.closePath();
ctx.fill();
...
How exactly does a generator comprehension work?
...em out of the expression, one by one.
>>> my_list = [1, 3, 5, 9, 2, 6]
>>> filtered_list = [item for item in my_list if item > 3]
>>> print(filtered_list)
[5, 9, 6]
>>> len(filtered_list)
3
>>> # compare to generator expression
...
>>> filte...
Generate random numbers following a normal distribution in C/C++
...
|
edited Dec 29 '18 at 3:27
MultiplyByZer0
3,73333 gold badges2727 silver badges4646 bronze badges
...
Face recognition Library [closed]
...
|
edited Jul 29 '13 at 0:11
hippietrail
13k1414 gold badges8484 silver badges125125 bronze badges
...
What's the maximum value for an int in PHP?
...
124
From the PHP manual:
The size of an integer is
platform-dependent, although a maximum
value of...
Find integer index of rows with NaN in pandas dataframe
...an use to index back into df, e.g.:
df['a'].ix[index[0]]
>>> 1.452354
For the integer index:
df_index = df.index.values.tolist()
[df_index.index(i) for i in index]
>>> [3, 6]
share
|
...