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rails 3 validation on uniqueness on multiple attributes
I use Rails 3.0.0.beta4
3 Answers
3
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How do I create a list of random numbers without duplicates?
... = f1.readlines()
for i in range(50):
lines = random.sample(all_lines, 40)
This way, you only need to actually read from the file once, before your loop. It's much more efficient to do this than to seek back to the start of the file and call f1.readlines() again for each loop iteration.
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Declaration suffix for decimal type
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Documented in the C# language specification, chapter 2.4.4:
float f = 1.2f;
double d = 1.2d;
uint u = 2u;
long l = 2L;
ulong ul = 2UL;
decimal m = 2m;
Nothing for int, byte, sbyte, short, ushort.
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What is the effect of encoding an image in base64?
If I convert an image (jpg or png) to base64, then will it be bigger, or will it have the same size? How much greater will it be?
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How Do I Fetch All Old Items on an RSS Feed?
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David DeanDavid Dean
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add a comm...
Tar archiving that takes input from a list of files
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answered Nov 7 '11 at 7:48
Martin YorkMartin York
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Foreign Key to multiple tables
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154
You have a few options, all varying in "correctness" and ease of use. As always, the right desig...
Setting a system environment variable from a Windows batch file?
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answered Sep 27 '10 at 14:49
Hugh AllenHugh Allen
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How to write an XPath query to match two attributes?
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4 Answers
4
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Can anyone explain python's relative imports?
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141
You are importing from package "sub". start.py is not itself in a package even if there is a __...