Sorting a multidimensional array by multiple keys

Paulo da Silva psdasilvaX at esotericaX.ptX
Mon Apr 2 04:03:23 CEST 2007


Rehceb Rotkiv escreveu:
> Hello everyone,
> 
> can I sort a multidimensional array in Python by multiple sort keys? A 
> litte code sample would be nice!

class MyList(list):
	# This is the index of the element to be compared
	CmpIndex=0

	# Comparision methods
	@staticmethod
	def __cmp_pars(x,y):
		if isinstance(x,MyList):
			x=x[MyList.CmpIndex]
		if isinstance(y,MyList):
			y=y[MyList.CmpIndex]
		return x,y
	def __cmp__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return cmp(s,o)
	def __lt__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return s<o
	def __le__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return s<=o
	def __gt__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return s>o
	def __ge__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return s>=o
	def __eq__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return s==o
	def __ne__(self,other):
		s,o=MyList.__cmp_pars(self,other)
		return s!=o

Use:

x=MyList(<list of lists>)
MyList.CmpIndex=2 # Compare by index 2
x.sort()

May be there is a better solution ...
HTH
Paulo



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