Check Parameter is Integer

Rails
1

Hiya,

A simple problem I expect, but I cannot seem to find a simple way to do
it.

How can I check to see if a parameter is a number or not. Bear in mind
it may be nil so I need to cope with that situation too.

Thanks,

~ Mark

2

Sorry, I should clarify that I mean a querystring parameter. As in:

(in a controller method)

params[:some_key]

3

if params[:some_key].to_i != 0

Granted, you’ll need a separate check if the number actually can be 0,
but
String#to_i returns 0 when there is no number.

Jason

4

Hi Mark,

Mark D. wrote:

How can I check to see if a parameter is a number or
not. Bear in mind it may be nil so I need to cope with
that situation too.

In your model…

validates_numericality_of :some_key

Check the doc at api.rubyonrails.org for a number of options.

hth,
Bill

5

Stefan M. wrote:

Jason R. wrote:

if params[:some_key].to_i != 0

Granted, you’ll need a separate check if the number actually can be 0, but
String#to_i returns 0 when there is no number.

Depending on the OPs needs he may want to use the method Integer and
rescue the ArgumentError - or just use Bills suggestion.

you can also try and match via regexp

params[:some_key] =~ /^\d+$/

6

Jason R. wrote:

if params[:some_key].to_i != 0

Granted, you’ll need a separate check if the number actually can be 0, but
String#to_i returns 0 when there is no number.

Depending on the OPs needs he may want to use the method Integer and
rescue the ArgumentError - or just use Bills suggestion.