大约有 47,000 项符合查询结果（耗时：0.0389秒） [XML]
In where shall I use isset() and !empty()
...mewhere that the isset() function treats an empty string as TRUE , therefore isset() is not an effective way to validate text inputs and text boxes from a HTML form.
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What is in your Mathematica tool bag? [closed]
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I've mentioned this before, but the tool I find most useful is an application of Reap and Sow which mimics/extends the behavior of GatherBy:
SelectEquivalents[x_List,f_:Identity, g_:Identity, h_:(#2&)]:=
Reap[Sow[g[#],{f[#]}]&/@x, _, h...
Python's equivalent of && (logical-and) in an if-statement
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what should i do for this: if x=='n' and y =='a' or y=='b': <do something> Will it work !? @ChristopheD
– diffracteD
Apr 2 '15 at 15:35
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UTF-8: General? Bin? Unicode?
I'm trying to figure out what collation I should be using for various types of data. 100% of the content I will be storing is user-submitted.
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In node.JS how can I get the path of a module I have loaded via require that is *not* mine (i.e. in
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require.resolve() is a partial answer. The accepted answer may work for many node modules, but won't work for all of them.
require.resolve("moduleName") doesn't give you the directory where the module is installed; it gives you the location of the file defined in the main attribute in the mod...
Why do we need virtual functions in C++?
...that eat() is called via an intermediate function (a trivial function just for this example):
// This can go at the top of the main.cpp file
void func(Animal *xyz) { xyz->eat(); }
Now our main function is:
Animal *animal = new Animal;
Cat *cat = new Cat;
func(animal); // Outputs: "I'm eating...
Efficient way to apply multiple filters to pandas DataFrame or Series
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Pandas (and numpy) allow for boolean indexing, which will be much more efficient:
In [11]: df.loc[df['col1'] >= 1, 'col1']
Out[11]:
1 1
2 2
Name: col1
In [12]: df[df['col1'] >= 1]
Out[12]:
col1 col2
1 1 11
2 2 12
In...
Practical usage of setjmp and longjmp in C
...ons can be used practically in embedded programming? I know that these are for error handling. But I'd like to know some use cases.
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Wolfram's Rule 34 in XKCD [closed]
...e, it turns black/positive/1/true/whatever`, etc. etc. until you see that, for rule 110, if a cell and its neighbors match rules 1,2,3,5,6, then the cell turns black. Otherwise, it turns white. A while back, I wrote some JS code to allow me to play around with these unique CA:
http://lucasoman.com/...
Cosine Similarity between 2 Number Lists
I need to calculate the cosine similarity between two lists , let's say for example list 1 which is dataSetI and list 2 which is dataSetII . I cannot use anything such as numpy or a statistics module. I must use common modules (math, etc) (and the least modules as possible, at that, to reduc...