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How to convert a number to string and vice versa in C++
...o-number conversion and vice-versa are built in into the standard library. All the following functions are present in <string> (as per paragraph 21.5).
string to numeric
float stof(const string& str, size_t *idx = 0);
double stod(const string& str, size_t *id...
dplyr: “Error in n(): function should not be called directly”
...ction" specification, like example below:
delay <- dplyr::summarise(by_tailnum,
count = n(),
dist = mean(distance, na.rm = TRUE),
delay = mean(arr_delay, na.rm = TRUE))
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Direct casting vs 'as' operator?
... tend to almost never use 2 since if something is not the right type, I usually expect an exception to occur. I have only seen a need for this return-null type of functionality with badly designed libraries which use error codes (e.g. return null = error, instead of using exceptions).
3 is not a ca...
NSDictionary - Need to check whether dictionary contains key-value pair or not
...uldn't we mistakenly think that the key isn't present in the dictionary at all?
– jbx72487
Feb 1 '13 at 18:51
13
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Disable a Button
...
I also get an error if I change (_ sender: ) to UIButton . The error reads: Value of type '(UIButton) -> ()' has no member 'isEnabled'
– user9470831
Feb 5 '19 at 4:25
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NSUserDefaults - How to tell if a key exists
I'm working on a small iPhone app, and I am using NSUserDefaults as my data persistence. It only has to keep track of a few things, such as some names and some numbers so I figure I might as well keep it simple.
...
How to resize a VirtualBox vmdk file
... iso from within the virtualbox settings).
P.S. If your new size is too small, you'll get the same error even with your new vdi file.
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Is it good style to explicitly return in Ruby?
...d
Was this meant to be a function that returned a value, or not? It's really hard to say what the developer meant, as it both assigns the instance variable, AND returns the value assigned as well.
Suppose much later, another programmer (perhaps not that familiar with how Ruby does returns based ...
What is the real overhead of try/catch in C#?
... to make here:
Firstly, there is little or NO performance penalty in actually having try-catch blocks in your code. This should not be a consideration when trying to avoid having them in your application. The performance hit only comes into play when an exception is thrown.
When an exception is th...
How can I remove all objects but one from the workspace in R?
I have a workspace with lots of objects and I would like to remove all but one. Ideally I would like to avoid having to type rm(obj.1, obj.2... obj.n) . Is it possible to indicate remove all objects but these ones ?
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