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How do you know when to use fold-left and when to use fold-right?
...re, you use a left fold. Example (haskell-style pseudocode)
foldl (-) [1, 2, 3] == (1 - 2) - 3 == 1 - 2 - 3 // - is left-associative
If your operator is right-associative (right fold), the parentheses would be set like this:
A x (B x (C x D))
Example: Cons-Operator
foldr (:) [] [1, 2, 3] == 1...
Convert a String representation of a Dictionary to a dictionary?
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1219
Starting in Python 2.6 you can use the built-in ast.literal_eval:
>>> import ast
>...
Decreasing for loops in Python impossible?
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220
for n in range(6,0,-1):
print n
# prints [6, 5, 4, 3, 2, 1]
...
Best way to format integer as string with leading zeros? [duplicate]
...n use the zfill() method to pad a string with zeros:
In [3]: str(1).zfill(2)
Out[3]: '01'
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How to get a DOM Element from a JQuery Selector
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266
You can access the raw DOM element with:
$("table").get(0);
or more simply:
$("table")[0];...
How to copy a dictionary and only edit the copy
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20 Answers
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Variable's scope in a switch case [duplicate]
..., however, create further nested scopes with braces as follows:
int key = 2;
switch (key) {
case 1: {
String str = "1";
return str;
}
case 2: {
String str = "2";
return str;
}
}
The resulting code will now compile successfully since the variable named str in each case clause i...
Pairwise crossproduct in Python [duplicate]
...
You're looking for itertools.product if you're on (at least) Python 2.6.
>>> import itertools
>>> a=[1,2,3]
>>> b=[4,5,6]
>>> itertools.product(a,b)
<itertools.product object at 0x10049b870>
>>> list(itertools.product(a,b))
[(1, 4), (1, 5), ...
C# '@' before a String [duplicate]
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answered Feb 2 '11 at 19:54
Mark AveniusMark Avenius
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