We do this by making the key a tuple: tuples are sorted first by their 1st element, then by their 2nd element. Thus if we want to impose an extra rule, we need to sort the list at a "higher level". Unfortunately 0 is an element of the integers and thus has a natural ordering: 0 is normally < 1,2,3.
SORTING PYTHON LIST OF DICTIONARIES HOW TO
(See "object rich comparison" for how to implicitly define cmp= in an elegant but possibly-excessive way.) Though legitimate, it gives us no major benefit (we'd have to duplicate code in an awkward manner), and a key function is more natural for your case. While a cmp function allows you to arbitrarily specify how two elements should compare (input: a, b output: ab or a=b). Īs for what is going on, there are two common ways to specify how a sorting algorithm works: one is with a key function, and the other is with a cmp function (now deprecated in python, but a lot more versatile). The is called the indexing/slice notation, see Explain Python's slice notation - Also note that someArray is common notation in many programming languages for indexing, but may not support slices of the form or. Itemgetter('rank') is the same thing as lambda x: x is the same thing as the function: def getRank(myDict): "Please could you explain to me (a Python novice) what it's doing? I can see that it's a lambda, which I know is an anonymous function: what's the bit in brackets?" – OP comment
> sorted(, key=lambda x:x if x!=0 else float('inf')) "I'd like to sort it by the rank values, ordering as follows: 1-2-3-4-0-0-0." -original poster > sorted(, key=lambda x:(x=0, x))
Option 2: key=lambda d:d if d!=0 else float('inf')
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