python - Why does assigning to self not work, and how to work around the issue? -

i have class (list of dicts) , want sort itself:

class table(list): …   def sort (self, in_col_name):     self = table(sorted(self, key=lambda x: x[in_col_name])) 

but doesn't work @ all. why? how avoid it? except sorting externally, like:

new_table = table(sorted(old_table, key=lambda x: x['col_name']) 

isn't possible manipulate object itself? it's more meaningful have:

class table(list):   pass 

than:

class table(object):   l = []   …   def sort (self, in_col_name):     self.l = sorted(self.l, key=lambda x: x[in_col_name]) 

which, think, works. , in general, isn't there any way in python object able change (not instance variable)?

you can't re-assign self within method , expect change external references object.

self argument passed function. it's name points instance method called on. "assigning self" equivalent to:

def fn(a):    = 2 = 1 fn(a) # still equal 1 

assigning self changes self name points (from 1 table instance new table instance here). that's it. changes name (in scope of method), , affect not underlying object, nor other names (references) point it.

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just sort in place using list.sort:

def sort(self, in_col_name):     super(table, self).sort(key=lambda x: x[in_col_name])