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How to overcome TypeError: unhashable type: 'list'
...used to compare dictionary keys during a dictionary lookup quickly.
Internally, hash() method calls __hash__() method of an object which are set by default for any object.
Converting a nested list to a set
>>> a = [1,2,3,4,[5,6,7],8,9]
>>> set(a)
Traceback (most recent call last...
Is it possible to have multiple statements in a python lambda expression?
...Q. Can you put multiple statements in a lambda?
A. No. But you don't actually need to use a lambda. You can put the statements in a def instead. i.e.:
def second_lowest(l):
l.sort()
return l[1]
map(second_lowest, lst)
Q. Can you get the second lowest item from a lambda by sorting the ...
Counting inversions in an array
...m to do the following: Given array A[1... n] , for every i < j , find all inversion pairs such that A[i] > A[j] . I'm using merge sort and copying array A to array B and then comparing the two arrays, but I'm having a difficult time seeing how I can use this to find the number of inversions...
Anonymous recursive PHP functions
... pass it by reference. Be aware, that if you modify the $factorial before calling the function, the result will change as it's passed by reference.
– Marius Balčytis
Sep 13 '12 at 21:48
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Group by multiple columns in dplyr, using string vector input
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Does the call to one_of() do anything here? I think it is redundant in this context, as the expression is wrapped in a call to vars().
– knowah
Aug 15 '19 at 14:13
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Change column type from string to float in Pandas
...ost) any other type (even if it's not necessarily sensible to do so). Also allows you to convert to categorial types (very useful).
infer_objects() - a utility method to convert object columns holding Python objects to a pandas type if possible.
convert_dtypes() - convert DataFrame columns to the ...
$_POST vs. $_SERVER['REQUEST_METHOD'] == 'POST'
Some guy called one of my Snipplr submissions "crap" because I used if ($_SERVER['REQUEST_METHOD'] == 'POST') instead of if ($_POST)
...
What's a good way to extend Error in JavaScript?
...nvironments set the stack property, but fileName and lineNumber are practically useless to be used in inheritance.
So, the minimalistic approach is:
function MyError(message) {
this.name = 'MyError';
this.message = message;
this.stack = (new Error()).stack;
}
MyError.prototype = new Er...
Unable to execute dex: GC overhead limit exceeded in Eclipse
...4-bit JVM. If you're on a 64 bit JVM, you can safely set it to anything smaller than your RAM size minus overhead for OS/other applications. On a 32 bit VM, you'll want to keep it smaller than about 1500M (on Linux) or 1100M (on Windows) because the VM needs to allocate contiguous address space, a...
How can I read a function's signature including default argument values?
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@Spi, you are calling inspect.getargspec on a module, not a function.
– Mike Graham
Apr 20 '10 at 17:36
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