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Benefits of using the conditional ?: (ternary) operator
What are the benefits and drawbacks of the ?: operator as opposed to the standard if-else statement. The obvious ones being:
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What does the “map” method do in Ruby?
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The map method takes an enumerable object and a block, and runs the block for each element, outputting each returned value from the block (the original object is unchanged unless you use map!):
[1, 2, 3].map { |n| n * n } #=> [1, 4, 9]
Array and Range are enume...
How is set() implemented?
...ython source code for set which, according to Achim Domma, is mostly a cut-and-paste from the dict implementation.
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pandas: multiple conditions while indexing data frame - unexpected behavior
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As you can see, the AND operator drops every row in which at least one
value equals -1. On the other hand, the OR operator requires both
values to be equal to -1 to drop them.
That's right. Remember that you're writing the condition in te...
What's the difference between a web site and a web application? [closed]
I'm stumped trying to come up to a difference between a website and a web application for myself. As I see it, a web site points to a specific page and a web application is more of some sort of 'portal' to content and information.
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Add spaces before Capital Letters
... work fine (I even voted up Martin Browns answer), but they are expensive (and personally I find any pattern longer than a couple of characters prohibitively obtuse)
This function
string AddSpacesToSentence(string text, bool preserveAcronyms)
{
if (string.IsNullOrWhiteSpace(text))
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How do I clone a Django model instance object and save it to the database?
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Just change the primary key of your object and run save().
obj = Foo.objects.get(pk=<some_existing_pk>)
obj.pk = None
obj.save()
If you want auto-generated key, set the new key to None.
More on UPDATE/INSERT here.
Official docs on copying model instances: h...
TypeError: got multiple values for argument
I read the other threads that had to do with this error and it seems that my problem has an interesting distinct difference than all the posts I read so far, namely, all the other posts so far have the error in regards to either a user created class or a builtin system resource. I am experiencing th...
Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
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Why don't C++ compilers define operator== and operator!=?
...ison or a deep (internal) comparison.
It's safer to just not implement it and let the programmer do that themselves. Then they can make all the assumptions they like.
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