How to rewrite the code more elegantly

Question

The code below reads lines from a file, then it executes the custom function (My_Function) and return values to the variables(e.g. condition_A)

  for line in input_file:
     if condition_A:
         condition_A = My_Function(A_tuple[0], B_tuple[0])

    if condition_B:
        condition_B = My_Function(A_tuple[1], B_tuple[1])

    if condition_C:
        condition_C = My_Function(A_tuple[2], B_tuple[2])

    if condition_D:
        condition_D = My_Function(A_tuple[3], B_tuple[3])

    if condition_E:
        condition_E = My_Function(A_tuple[4], B_tuple[4])

...

My question is: can the code be modified to more elegant version? After all, many code is similar(I don't want to define another function to simplify it because the code is still similar after the new function is defined). thanks.

Could you be more specific about what the conditions are? Are you testing the line for equality to various things, or is it more complicated than that? — Zhehao Mao, Jun 21 '11 at 17:09
I'm voting to close this question as off-topic because code refactoring should be asked about on Code Review, not Stack Overflow. — TylerH, Feb 10 '17 at 15:08

score 8 · Accepted Answer · answered Jun 21 '11 at 17:07

8

Instead of having 5 variables condition_*, use a list, conditions:

conditions=[1]*5 # initialize conditions as you wish
for line in input_file:
    for i,condition in enumerate(conditions):
        if condition:
            conditions[i]=My_Function(A_tuple[i],B_tuple[i])

answered Jun 21 '11 at 17:07

unutbu

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+1: this is very clean and fits the given example most nicely. – André Caron Jun 21 '11 at 17:10

senderle · Answer 2 · 2011-06-21T17:14:17.493

1

What about something like

conditions = [condition_A, condition_B, condition_C, condition_D, condition_E]
condition_test = lambda c, i: My_Function(A_tuple[i], B_tuple[i]) if c else c
for line in input_file:
    conditions = [condition_test(c, i) for i, c in enumerate(conditions)]

edited Jun 21 '11 at 17:14

answered Jun 21 '11 at 17:07

senderle

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score 0 · Answer 3 · answered Jun 21 '11 at 17:09

0

'line' is not referenced in teh loop, is that an error in simplifying it for posting?

How about

condition=1 #or 2 or...
for line in input_file:
   My_Function(A_tuple[condition],B_tuple[condition])

answered Jun 21 '11 at 17:09

Pete

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Sorry, that's not equivalent is it. – Pete Jun 21 '11 at 17:11

score 0 · Answer 4 · answered Jun 21 '11 at 17:11

Before refactoring your code on a purely syntactic level (which is covered in examples above), it might be useful to evaluate what you're doing with the code on a functional level

Check out your condition_x variables. I think you might be using the same variable for two different things (both type-wise and logically) - usually a bad idea in a weakly typed language. It looks to me as if the user sets a condition to true or false, and then that condition is assigned the output - is the output boolean? is it related to the original value of that variable? Rethinking this might lead to more understandable code.

It is also difficult to evaluate how this can be refactored without seeing what goes in to condition_x - since these might have commonalities.

score 0 · Answer 5 · answered Jun 21 '11 at 17:27

0

One more sample(not solution) based on unutbu's:

data = [1,2,3,'',4,5,6, '', 0]
for i in (i for i in xrange(len(data)) if data[i] not in ['',0]):
    data[i] += 1

Sorry if duplicate

answered Jun 21 '11 at 17:27

Artsiom Rudzenka

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score 0 · Answer 6 · answered Jun 21 '11 at 17:31

Here is a generic solution where you can have custom index and you can also access conditions by name if need be and it can be easily extended to add any new complexities

class Condition(object):
    def __init__(self, active, index1, index2):
        self.active = active
        self.index1 = index1
        self.index2 = index2

conditions = {
    'A': Condition(True,0,0),
    'B': Condition(True,1,1),
    'C': Condition(True,2,2),
    'D': Condition(True,3,3),
    'E': Condition(True,4,4),
}

for line in input_file:
    for condition in conditions.itervalues():
        if condition.active:
            condition.active = My_Function(A_tuple[condition.active.index1], B_tuple[condition.active.index2])

How to rewrite the code more elegantly

6 Answers6