大约有 15,000 项符合查询结果（耗时：0.0259秒） [XML]
Can't subtract offset-naive and offset-aware datetimes
I have a timezone aware timestamptz field in PostgreSQL. When I pull data from the table, I then want to subtract the time right now so I can get it's age.
...
Is int[] a reference type or a value type?
I know an int is a value type, but what are arrays of value types? Reference types? Value types? I want to pass an array to a function to check something. Should I just pass the array, as it will just pass the reference of it, or should I pass it as ref?
...
Haversine Formula in Python (Bearing and Distance between two GPS points)
I would like to know how to get the distance and bearing between 2 GPS points .
I have researched on the haversine formula.
Someone told me that I could also find the bearing using the same data.
...
Begin, Rescue and Ensure in Ruby?
I've recently started programming in Ruby, and I am looking at exception handling.
7 Answers
...
How does deriving work in Haskell?
Algebraic Data Types (ADTs) in Haskell can automatically become instances of some typeclasse s (like Show , Eq ) by deriving from them.
...
Amazon S3 boto - how to create a folder?
How can I create a folder under a bucket using boto library for Amazon s3?
11 Answers
...
Android get free size of internal/external memory
I want to get the size of free memory on internal/external storage of my device programmatically. I'm using this piece of code :
...
What is unit testing? [closed]
I saw many questions asking 'how' to unit test in a specific language, but no question asking 'what', 'why', and 'when'.
20...
How can I remove non-ASCII characters but leave periods and spaces using Python?
I'm working with a .txt file. I want a string of the text from the file with no non-ASCII characters. However, I want to leave spaces and periods. At present, I'm stripping those too. Here's the code:
...
Efficiently convert rows to columns in sql server
I'm looking for an efficient way to convert rows to columns in SQL server, I heard that PIVOT is not very fast, and I need to deal with lot of records.
...