pagination logic in calculating total of pages

Question

I'm using a react component that need me to pass in below prop

<Pager 
      totalPages={10}
      currentPage={1}
/>

I can't figure out the calculation as in the api I have total_items, not totalPages. if I have 50 total_items, how can I produce 5 for the totalPages prop? says my limit is 10.

@VamshiGudipati https://www.npmjs.com/package/react-toolbox-additions — Cecilia Chan, Sep 08 '17 at 03:39
total_items / 10 should give you the number of pages. You also need to consider remainder of the division (total_items % 10). So total pages would be total_items / 10 and 1 more in case remainder is > 0. — Umesh, Sep 08 '17 at 03:41

score 125 · Accepted Answer · answered Sep 08 '17 at 03:38

125

Divide total_items by limit, and round the value up.

Math.ceil(total_items/limit);

50 items / 10 per page = 5 pages
55 items / 10 per page = 6 pages

answered Sep 08 '17 at 03:38

fubar

16,918
4
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Returns `0` if `items < perpage`. – saman.shahmohamadi Feb 26 '19 at 11:59
@saman.shahmohamadi if you’re using `Math.ceil` that’s not possible, unless the number of items is 0. E.g. `Math.ceil(1/10) = 1` – fubar Feb 26 '19 at 12:21
3

For other languages that might be passing total_items as an integer you will need to convert to a float. E.g., in Ruby `(total_items.to_f / limit).ceil` – Gerry Shaw May 02 '19 at 00:07
3

When you desire having 1 when `total_items === 0`, you can use `Math.ceil(total_items/limit)||1`; – massic80 Jun 11 '21 at 11:28

score 0 · Answer 2 · answered Aug 28 '23 at 18:54

0

integer only calculation:

int total_pages = total_items==0 ? 0 : (total_items - 1) / page_size + 1;

answered Aug 28 '23 at 18:54

user3088037

83
6

score -6 · Answer 3 · edited Jan 02 '18 at 13:38

-6

you need to check if there is a quotient from the divide operation because there is apparently few items need to be showed in another page

for example:

6 items
5 limit

if we just divide and ceil we will get 1 which is incorrect because there is one item need an extra page to be counted

totalPages_pre = (total_items/limit)
totalPages = (search.total % page_size) == 0 ? totalPages_pre : totalPages_pre + 1

edited Jan 02 '18 at 13:38

Umair

6,366
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answered Jan 02 '18 at 12:49

Ashraf

9
1

1

`Math.ceil()` does give higher number (2 in this case). – Bogac Jun 03 '18 at 06:06
This statement is actually correct "if we just divide and ceil we will get 1", this is caused by java's integer arithmetic, Math.ceil expects a double but dividing `integer / integer` returns `integer` – emont01 Jun 28 '21 at 03:24

pagination logic in calculating total of pages

3 Answers3