大约有 40,910 项符合查询结果（耗时：0.0247秒） [XML]
find() with nil when there are no records
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Yes, just do:
Challenge.find_by_id(10)
For Rails 4 and 5:
Challenge.find_by(id: 10)
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Practical non-image based CAPTCHA approaches?
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103 Answers
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Common MySQL fields and their appropriate data types
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answered Dec 10 '08 at 0:57
da5idda5id
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What is the proper #include for the function 'sleep()'?
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edited Dec 10 '19 at 10:16
Daniel Selvan
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adding noise to a signal in python
I want to add some random noise to some 100 bin signal that I am simulating in Python - to make it more realistic.
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Does it make sense to use “as” instead of a cast even if there is no null check? [closed]
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edited Jan 27 '10 at 23:56
answered Jan 26 '10 at 14:01
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How to quit scala 2.11.0 REPL?
In the last version of scala (2.10.3) REPL, I can type exit to quit from REPL. However, in Scala 2.11.0 this doesn't work.
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for each loop in Objective-C for accessing NSMutable dictionary
... every class that conforms to the NSFastEnumeration protocol (available on 10.5+ and iOS), though NSDictionary is one of the few collections which lets you enumerate keys instead of values. I suggest you read about fast enumeration in the Collections Programming Topic.
Oh, I should add however that...
Multiple select statements in Single query
...re is even a far better way, see my answer.
– Pentium10
Feb 13 '10 at 9:45
4
"Operand should cont...
Accessing localhost:port from Android emulator
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You can access your host machine with the IP address "10.0.2.2".
This has been designed in this way by the Android team. So your webserver can perfectly run at localhost and from your Android app you can access it via "http://10.0.2.2:<hostport>".
If your emulator must ...