split the code with big variable names over two lines in python

Question

I want to split python code over two lines, my code is something similar to:

if long_named_three_d_array[first_dimension][second_dimension][third_dimension] == somevalue:
    //dosomething

I want to split above if condition over two lines.

Please help. Thanks.

Answer 1

In Python, the LHS can be bracketed.

>>> a = {}
>>> a[1] = {}
>>> a[1][2] = {}
>>> (a[1][2]
... [3]) = ''
>>> a
{1: {2: {3: ''}}}
>>> (b) = 2
>>> b
2

This means you can write your line as

if (long_named_three_d_array[first_dimension] 
    [second_dimension]
    [third_dimension] ) == somevalue:
# Rest of code here, obviously properly indented in for the if.

Answer 2

You can use the line break continuation character, \ .

if long_named_three_d_array[first_dimension] \
    [second_dimension]\
    [third_dimension] == somevalue:
# Rest of code here, obviously properly indented in for the if.

Answer 3

One approach would be to use a temporary variable:

tmp = long_named_three_d_array[first_dimension][second_dimension][third_dimension] 
if tmp == somevalue:
    //dosomething

though shorter, yet descriptive variable identifiers would be a better choice if that's possible.