Python: Is there a simpler way to do this script? [closed]

Question

I am trying to make self.id show exact value. I made it but I'm wondering how can I improve it?

self.id = 36

def OnClickNextPage(self):
    if self.id == 36:
        self.id = 37
    elif self.id == 37:
        self.id = 1020
    elif self.id == 1020:
        self.id = 2020
    elif self.id == 2020:
        self.id = 3019
    elif self.id == 3019:
        self.id = 5015
    elif self.id == 5015:
        self.id = 7019
    else:
        return

def OnClickPrevPage(self):
    if self.id == 36:
        return
    elif self.id == 37:
        self.id = 36
    elif self.id == 1020:
        self.id = 37
    elif self.id == 2020:
        self.id = 1020
    elif self.id == 3019:
        self.id = 2020
    elif self.id == 5015:
        self.id = 3019
    elif self.id == 7019:
        self.id = 5015
    else:
        return

I expect to get the exact value, but I'm not really sure how to make it smarter.

Answer 1

If you're just looking to shorten it, you can use lists for self.id values and the values you want to change it to. For the first function:

def OnClickNextPage(self):
    possible_ids = [36, 37, 1020, 2020, 3019, 5015]
    change_id = [37, 1020, 2020, 3019, 5015, 7019]
    if self.id in possible_ids:
        self.id = change_id[possible_ids.index(self.id)]
        return self
    else:
        return self

Make sure you return self so that it updates self.id for the object.

Answer 2

You can make the IDs a list and keep track of which page (index) you're on instead. Make id a property so that you can easily calculate it based on the current index as needed:

class Pages:
    def __init__(self, ids):
        self.ids = ids
        self.index = 0

    @property
    def id(self):
        return self.ids[self.index]

    def OnClickNextPage(self):
        self.index += 1

    def OnClickPrevPage(self):
        self.index -= 1

pages = Pages([36, 37, 1020, 2020, 3019, 5015])
print(pages.id)
pages.OnClickNextPage()
print(pages.id)
pages.OnClickNextPage()
print(pages.id)
pages.OnClickPrevPage()
print(pages.id)

This outputs:

36
37
1020
37