大约有 42,000 项符合查询结果（耗时：0.0414秒） [XML]
Rails: How do I create a default value for attributes in Rails activerecord's model? [duplicate]
I want to create a default value for an attribute by defining it in ActiveRecord. By default everytime the record is created, I want to have a default value for attribute :status . I tried to do this:
...
How can I make git ignore future revisions to a file?
I have created a default version of a file included in a git repository. It's important that when someone clones the repository, they get a copy of this file. However, I would like to set git so that it ignores changes to this file later. .gitignore works only on untracked files.
...
Is there a decorator to simply cache function return values?
...
16 Answers
16
Active
...
How can I validate a string to only allow alphanumeric characters in it?
How can I validate a string using Regular Expressions to only allow alphanumeric characters in it?
10 Answers
...
Why is exception.printStackTrace() considered bad practice?
There is a lot of material out there which suggests that printing the stack trace of an exception is bad practice.
9 An...
“using namespace” in c++ headers
In all our c++ courses, all the teachers always put using namespace std; right after the #include s in their .h files. This seems to me to be dangerous since then by including that header in another program I will get the namespace imported into my program, maybe without realizing, intending or...
Underscore: sortBy() based on multiple attributes
I am trying to sort an array with objects based on multiple attributes. I.e if the first attribute is the same between two objects a second attribute should be used to comapare the two objects. For example, consider the following array:
...
Does Java have a HashMap with reverse lookup?
I have data that is organized in kind of a "key-key" format, rather than "key-value". It's like a HashMap, but I will need O(1) lookup in both directions. Is there a name for this type of data structure, and is anything like this included in Java's standard libraries? (or maybe Apache Commons?)
...
Why doesn't JavaScript support multithreading?
Is it a deliberate design decision or a problem with our current day browsers which will be rectified in the coming versions?
...
Has anyone used Coffeescript for a production application? [closed]
Coffeescript looks pretty cool. Has anyone used it? What are its Pros & Cons?
7 Answers
...