Python: increasing array indexes

Question

I have a random csv file containing random numbers, comma separated. I'm doing some iteration, in order to filter data

if (int(row[0]) + i == int(row[1])) and int(row[1]) + i == int(row[2]) and int(row[2]) + i == int(row[3]) and int(row[3]) + i == int(row[4]):
    do something
elif (int(row[0]) + i == int(row[1])) and int(row[1]) + i == int(row[2]) and int(row[2]) + i == int(row[3]):
    do something

The If statements are so much more than that. My code obviously works perfectly, since there's nothing special about it.

I just wish to find a way to do what I'm doing without having to type

if row[0] and row[1] and row[2] and...

say the maximum is row[4] as shown in the example above,basically, i want to something, like a recursive function to do:

for n in range of 0 to 4
    if row[n] +i == row[n+1]:
        do something
        row[n] == row[n-1]
           if row[n-1] ...

I'm not quite sure how to do this, I hope my question is clear. I think this is a similar question in C#.

The part that I don't really know how to do, is how to get rid of and, I mean if i should write if... and ...and then I could just copy paste and do what I was doing, I want a better solution, if it exists.

If a solution exists, I'd prefer if it's a recursive one, because I am working hard to get rid of loops in my code.

if all(int(row[n])+i==int(row[n+1]) for n in range(4)): ... — khelwood
– khelwood, Commented Jun 30, 2015 at 20:24
"If a solution exists, I'd prefer if it's a recursive one, because I am working hard to get rid of loops in my code." Why? Recursion is not one of python's strong suits. Generally you'd want to go the other way: remove recursion and replace it with an iterative approach. — jme
– jme, Commented Jun 30, 2015 at 20:28
Are you trying to see if everything in a particular row has the same value? — user107498
– user107498, Commented Jun 30, 2015 at 20:30
Are you primarily looking for a solution for checking a particular length of row values, like your example with 4, or to find out how many values in a row have this property? — Dan Getz
– Dan Getz, Commented Jun 30, 2015 at 20:31

Dan Getz · Accepted Answer · 2015-06-30 20:40:14Z

1

You can compare with a range:

if [int(x) for x in row[0:4]] == range(int(row[0]), int(row[0]) + 4 * i, i):

The right-hand side will be integers in the range from row[0] through row[0] + 3 * i, in increments of i.

If you're always treating these rows as integers, it might be simpler to convert your row into a list of int beforehand:

row = [int(x) for x in row]

So that you can write the condition more simply:

if row[0:4] == range(row[0], row[0] + 4 * i, i):

edited Jun 30, 2015 at 20:40

answered Jun 30, 2015 at 20:28

Dan Getz

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1 Comment

Lynob Over a year ago

if [int(x) for x in row[0:4]] == range(int(row[0]), int(row[0]) + 4 * i, i):

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