大约有 45,000 项符合查询结果（耗时：0.0281秒） [XML]
@UniqueConstraint annotation in Java
I have a Java bean. Now, I want to be sure that the field should be unique.
8 Answers
...
What is the difference between a mutable and immutable string in C#?
...ects themselves could change, and the data structure would have no way of knowing, leading to corrupt data that would, eventually, crash your program.
However, you can change its contents- so it's much, much more memory efficient than making a complete copy because you wanted to change a single cha...
How do I check if a string is a number (float)?
...NaN')
nan
Otherwise, I should actually thank you for the piece of code I now use extensively. :)
G.
share
|
improve this answer
|
follow
|
...
Importing variables from another file?
...iables from file1 without flooding file2's namespace, use:
import file1
#now use file1.x1, file2.x2, ... to access those variables
To import all variables from file1 to file2's namespace( not recommended):
from file1 import *
#now use x1, x2..
From the docs:
While it is valid to use from ...
Read a file in Node.js
...
With Node 0.12, it's possible to do this synchronously now:
var fs = require('fs');
var path = require('path');
// Buffer mydata
var BUFFER = bufferFile('../public/mydata.png');
function bufferFile(relPath) {
return fs.readFileSync(path.join(__dirname, relPath));...
What is the best project structure for a Python application? [closed]
...
Oh, I love this trick and am using it now. I want to put the shared module in another directory, and I do not want to install module system-wide, nor do I want to ask people to modify PYTHONPATH manually. Unless people propose something better, I think this is ac...
Cannot kill Python script with Ctrl-C
...s keep the main thread alive:
import time
while True:
time.sleep(1)
Now it will keep print 'first' and 'second' until you hit Ctrl+C.
Edit: as commenters have pointed out, the daemon threads may not get a chance to clean up things like temporary files. If you need that, then catch the Keyboa...
bash: pip: command not found
...et install python3-pip
to install pip3.
Old 2013 answer (easy_install is now deprecated):
Use setuptools to install pip: sudo easy_install pip
(I know the above part of my answer is redundant with klobucar's, but I can't add comments yet), so here's an answer with a solution to sudo: easy_install:...
What is SQL injection? [duplicate]
...erabilities because attackers can send values to an application that they know will be interpolated into a SQL string. By being very clever, they can manipulate the result of queries, reading data or even changing data that they shouldn't be allowed to do.
Example in PHP:
$password = $_POST['pass...
Why does running the Flask dev server run itself twice?
...######### Restarting @ {} ###################'.format(
datetime.utcnow())
However, if you need to set up module globals, then you should instead use the @app.before_first_request decorator on a function and have that function set up such globals. It'll be called just once after every reloa...