Random Integer for Text Field

Rails
1

Hello, I would like to populate an empty text field with a 5 digit
random integer upon an ajax request. I am new to programming and this is
all I have so far:

rand()

It will be used for my _form.rhtml partial (a persons 5 digit ID number)
so I’m wondering if something like this would belong in a helper, model,
or view?
Thanks for any help!

2

Hello, I would like to populate an empty text field with a 5 digit
random integer upon an ajax request. I am new to programming and this is
all I have so far:

rand()

It will be used for my _form.rhtml partial (a persons 5 digit ID number)
so I’m wondering if something like this would belong in a helper, model,
or view?
Thanks for any help!

helper or model depending on the day I suppose… but I’m not sure I’d
do
this… just because you use rand() doesn’t mean that it’s going to be
unique and I’m guessing you’d like your users 5 digit ID numbers to be
unique, yeah?

Just something to think about…

3

The ID number will mainly be used to keep track of the person’s
attendance. The person will check in via USB numeric keypad and if the
5 digit numbers are too close or similiar there is more room for error
(checking in wrong person because numbers are so close). I figured if
the numbers are random they will be spread out more from each other and
hence less room for error. The number of people will most likely be
under 500.
To make each ID number unique I could use a validation for uniqueness.
If there is a better way to do all of this please let me know. Thanks!

4

Justin Ko wrote:

The ID number will mainly be used to keep track of the person’s
attendance. The person will check in via USB numeric keypad and if the
5 digit numbers are too close or similiar there is more room for error
(checking in wrong person because numbers are so close). I figured if
the numbers are random they will be spread out more from each other and
hence less room for error. The number of people will most likely be
under 500.
To make each ID number unique I could use a validation for uniqueness.
If there is a better way to do all of this please let me know. Thanks!

rand generates a random number between 0 and 1. You can give an integer
argument to rand to define the upper limit of the numbers.

rand(1000) #=> 297

So you can add this to your model’s initialize method. This will make
sure that every new object has a random id.

class Foo < ActiveRecord::Base
def initialize
self[:code] = rand(1000)
end
end

This doesn’t handle the unique problem however.

5

Okay this is heavier then I anticipated. I’m going to learn some more
Ruby … Thanks for the suggestions!

6

I would submit that you do this in the model as a called function of the
creating/inserting function and loop around the rand until a unique id
is found.

ps. don’t forget to seed the rand otherwise it would become vary
inefficient.