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+--- Thread: modifying a list in an expression (/thread-16096.html)
modifying a list in an expression - Skaperen - Feb-14-2019
i have some incoming data. each unit of data can be converted to a list. that list can be converted back to that data. the conversions are expressions. i can nest these two expression to convert the data to a list and then back. i have a modification to the data that is defined in terms of it being in the list form. the modification is copying element index B to element index A of the list like. i can do this in 3 lines:
temp = convert_data_to_list(data)
temp[A] = temp[B]
data = convert_list_to_data(temp)is there an easy way to use slicing (or something else) to make this all be a single expression?
RE: modifying a list in an expression - perfringo - Feb-14-2019
Something like this (as you can see it's readability is not great)?
convert_list_to_data([convert_data_to_list(data)[B] if convert_data_to_list(data).index(x) == A else x for x in convert_data_to_list(data)])
RE: modifying a list in an expression - Skaperen - Feb-15-2019
that's also going to be slow. the code i gave is actually going to be in a loop affecting many units of data (each unit can be converted to a list). most units are strings and conversion to a list was a workaround because they are immutable. i guess squeezing this to a big expression in one line is just not going to happen.
and, yeah, it is harder to read. so i guess it's back to separate steps.