notation

问题 Writing floats to a CSV writes some of them like this: 2.0628800997782577e-05 c = csv.writer(open(file, "wb")) c.writerow([var1, var2]) What I've tried: I have already tried var1**8 following other answers on StackOverflow, but this simply raises them to the power of 8. I have also tried Decimal(var1), but this does not suppress the scientific notation. This makes it difficult to process the output in excel afterwards as it's recognized as text and not a number. How can I print it in non

问题 In the companies I've been working, I've seen a lot the use of prefixes to indicate the scope or the origin of variables, for example m for classes members, i for methods intern variables and a (or p ) for methods parameters: public class User { private String mUserName; public String setUserName(final String aUserName) { final String iUserName = "Mr " + aUserName; mUserName = iUserName; } } What do you think about it? Is it recommended (or precisely not)? I found it quite ugly in a first

问题 Absolutely basic Java question which I'm having a hard time finding on Google. What does the following mean: (7 & 8) == 0? Is that equivalent to writing: 7 == 0 || 8 == 0? I wrote a quick main which tests this, and it seems to be the case. I just wanted to make sure I'm not missing anything. 回答1: Nope. & is bitwise and. It sets a bit if the corresponding bits are set in both inputs. Since in binary, 7 is 111 and 8 is 1000 , they have no bits in common, so the result is 0 . There isn't really

问题 I'm getting terribly confused by the colon notation used when defining/calling Lua functions. I thought I'd got my head round it until I saw this piece of code: function string.PatternSafe( str ) return ( str:gsub( ".", pattern_escape_replacements ) ); end function string.Trim( s, char ) if char then char = char:PatternSafe() else char = "%s" end return string.match( s, "^" .. char .. "*(.-)" .. char .. "*$" ) or s end What's confusing me here is that string.PatternSafe() doesn't reference

问题 Python seems to have an inconsistency in what kind of keys it will accept for dicts. Or, put another way, it allows certain kinds of keys in one way of defining dicts, but not in others: >>> d = {1:"one",2:2} >>> d[1] 'one' >>> e = dict(1="one",2=2) File "<stdin>", line 1 SyntaxError: keyword can't be an expression Is the {...} notation more fundamental, and dict(...) just syntactic sugar? Is it because there is simply no way for Python to parse dict(1="one") ? I'm curious... 回答1: This is not

问题 I am trying to use an Open Type music font called Bravura Text. I want to use that font in an application that I am currently developing. I did a little research on the features of Bravura Text and the documentation of the font points out, that it is possible to write notes and adjust their vertical position on a staff . There are special characters to raise/lower a notehead on the staff to represent the different tones. I tried to use that features in text applications like Word 2013, Open

问题 So, I've just learned that instead of writing things like: [1,2,3,4,5].inject {|x,y| x + y} => 15 I could write [1,2,3,4,5].inject(:+) => 15 I also learned that instead of writing [1,2,3,4,5].select {|x| x.even?} => [2,4] I could write [1,2,3,4,5].select(&:even?) => [2,4] My question is why one (select) uses the & and the other one (inject) doesn't. I'm sure that the : are because even? and + are treated at symbols, but I'd love clarification behind why the & is used in one and why the : are

问题 I have an object within another object, which im trying to get the value but it always returns "unexpected identifier". snow: Object {3h: 1.3} console.log(data.snow.3h) //returns Uncaught SyntaxError: Unexpected identifier console.log(data.snow) //returns Object {3h: 1.3} So how can i get the value of 3h ? 回答1: data.snow['3h']; Properties accessed with dot notation can't begin with a number. snow: Object {3h: 1.3} could be refactored to snow: {3h: 1.3} . It is redundant to type Object . Also,

问题 I'm new to C and looking at Go's source tree I found this: https://code.google.com/p/go/source/browse/src/pkg/runtime/race.c void runtime∕race·Read(int32 goid, void *addr, void *pc); void runtime∕race·Write(int32 goid, void *addr, void *pc); void runtime·raceinit(void) { // ... } What do the slashes and dots (·) mean? Is this valid C? 回答1: IMPORTANT UPDATE: The ultimate answer is certainly the one you got from Russ Cox, one of Go authors, on the golang-nuts mailing list. That said, I'm

问题 I need to know what += does in python. It's that simple. I also would appreciate links to definitions of other short hand tools in python. 回答1: In Python, += is sugar coating for the __iadd__ special method, or __add__ or __radd__ if __iadd__ isn't present. The __iadd__ method of a class can do anything it wants. The list object implements it and uses it to iterate over an iterable object appending each element to itself in the same way that the list's extend method does. Here's a simple