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What are the “standard unambiguous date” formats for string-to-date conversion in R?
... '"%Y-%m-%d"' then '"%Y/%m/%d"' on the first non-'NA' element,
and give an error if neither works.
as.Date("01 Jan 2000") yields an error because the format isn't one of the two listed above. as.Date("01/01/2000") yields an incorrect answer because the date isn't in one of the two fo...
Paging UICollectionView by cells, not screen
I have UICollectionView with horizontal scrolling and there are always 2 cells side-by-side per the entire screen. I need the scrolling to stop at the begining of a cell. With paging enabled, the collection view scrolls the whole page, which is 2 cells at once, and then it stops.
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What are valid values for the id attribute in HTML?
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For HTML 4, the answer is technically:
ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
HTML 5 is even more permissive, saying onl...
When should I write the keyword 'inline' for a function/method?
... unit but don't complain if it isn't defined. The linker will sort it out and make sure all the code that tried to use some extern symbol has its address.
inline - this function will be defined in multiple translation units, don't worry about it. The linker needs to make sure all translation units...
Writing handler for UIAlertAction
I'm presenting a UIAlertView to the user and I can't figure out how to write the handler. This is my attempt:
9 Answers
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Print string to text file
...ext_file.write("Purchase Amount: {0}".format(TotalAmount))
For python2.7 and higher you can use {} instead of {0}
In Python3, there is an optional file parameter to the print function
with open("Output.txt", "w") as text_file:
print("Purchase Amount: {}".format(TotalAmount), file=text_file)
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BLE协议—广播和扫描 - 创客硬件开发 - 清泛IT社区，为创新赋能！
...广播方式的报文有4种，分别为可连接的非定向广播（ADV_IND）、可连接的定向广播（ADV_DIRECT_IND）、可扫描非定向广播（ADV_SCAN_IND）、不可连接的非定向广播（ADV_NONCONN_IND）
4种广播的使用场景各不相同
可连接的非定向广播（ADV...
Alphabet range in Python
...', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
And to do it with range
>>> list(map(chr, range(97, 123))) #or list(map(chr, range(ord('a'), ord('z')+1)))
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v...
Ask for User Permission to Receive UILocalNotifications in iOS 8
...ion to show notifications from your app, this applies for both remote/push and local notifications. In Swift you can do it like this,
Update for Swift 2.0
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
// Override point for...
Creating an empty bitmap and drawing though canvas in Android
I'd like to create an empty bitmap and set a canvas to that bitmap and then draw any shape on the bitmap.
2 Answers
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