In the view of a rail's app, I want to achieve:
If user's height isn't nil: return the height value with string "cm"
Otherwise: return string "N/A".
I'm wondering if there's a way to do this. The code below:
user.try(:profile_name).try(:push("as Alias")) || "N/A"
isn't working. The part try(:push("cm")) gives me an error. I thought of using the << operator to append strings by using , but I think there should be a neater way to complete this. Is there anyone who can give me a hint?
--another similar example which I want to accomplish but not working:
user.try(:height).try(:to_s).try(:push("cm")) || "N/A"
How about:
(user && user.profile.present?) ? "#{user.profile} as Alias" : 'N/A'
Related
I am trying to populate a text field on my GSP as such:
<label>Phone(aaa-bbb-cccc):</label> <g:textField name="phone" style ="border-radius: 5px"
value="${recordToEdit.telephones = [] ? null : recordToEdit.telephones.first()}"></g:textField><br>
but it still tell me I can't access first() on an empty list. telephones is a List of Strings each being a phone number.
as #gross-jonas pointed out, the recordToEdit.telephones = [] ? .. : .. is terribly wrong already, unless it's a typo
the check you are trying to make should look like:
value="${recordToEdit.telephones ? recordToEdit.telephones.first() : ''}"
or
value="${recordToEdit.telephones?.getAt( 0 ) ?: ''}"
You can just use the Null Safe Operator (?.) as
${recordToEdit.telephones?.first()}
for null checks, which is not sufficient.
UPDATE
for empty list checks and null checks,
${ recordToEdit.telephones ? recordToEdit.telephones[0] : '' }
will be good.
Dude, didn't you just mean == instead of = ?
It looks like you are overwriting your telephones which get issued successfully instead of comparing it.
In the process of learning ruby (I have a java background).
I have assignment statements where the value of one hash[:name_field] is being assigned to another. But the value coming from the hash on the right was sometimes blank. This was crashing my code hence i added the ternary logic with .nil ? etc....
I am surprised though that this doesn't work... The error is :
undefined method `nil' for 1133:Fixnum (NoMethodError)
Below is the code:
people_traffic.each do |person|
person_record = DaysTraffic.new
person_record[:name] = person[:name_filed].nil ? 0 : person[:name_filed]
person_record[:age] = person[:age_field].nil ? 0 : person[:age_field]
person_record.save
end
Why am I getting the (NoMethodError) for the nil?
Thank you!
It should be .nil? (with a question mark) not .nil. So in your case, that would be:
person_record[:name] = person[:name_filed].nil? ? 0 : person[:name_filed]
You can actually write this much simpler like so:
person_record[:name] = person[:name_filed] || 0
Because #to_i turns nil into 0, a good way to write something like this is:
person_record[:age] = person[:age_field].to_i
I have this simple condition in my ruby code:
if user.text != ("Empty" || "Damaged")
do something...
the thing is that when it is "Damaged" it still enters the loop, so I have to use this:
if user.text != "Empty"
if user.text != "Damaged"
...
..
What is the correct syntax to make the first one work?
Thanks!
Use this:
unless ["Empty", "Damaged"].include?(user.text)
...
end
The problem with your first approach is that a || b means that: if a != nil then it is a, else it is b. As you can see it is good for variables, not constants as they are rarely nil. Your expression ("Empty" || "Damaged") simply equals "Empty".
You want to use the this as a binary operator, the correct form would be:
if (user.text != "Empty") && (user.text != "Damaged")
The upper solution is just shorter. It consists of an array of elements you want to avoid, and you just simply check is the user.text is not present in it.
#Matzi has the right answer, for sure. But here's why what you're doing is failing:
Your statement ("Empty" || "Damaged") evaluates to "Empty"
You're saying return either one of these, whichever non-false thing you find first. In Ruby, any string, number or Object returns true, so you return "Empty" every time.
A better way to lay it out if you really want to use an if statement:
if user.text != "Empty" && user.text != "Damaged"
...
end
I assume, by the way, that you're trying to say "If the user text is neither Damaged nor Empty".
Hope that helps.
if ((text != "Empty") && (text != "Damaged"))
I have another probably basic problem. happy if u can help.
there is a request parameter 'action'. if I write :
<label><s:property value="%{#parameters.action}"/></label>
the value appears (it is 1)
So itry to test now :
<s:if test="%{#parameters.action == '1'}">YES 1</s:if><s:else>NOT 1</s:else>
NOT 1 appears.
I have tries all the syntaxes I found on the net for the test. Nothing changes, NOT 1 still displays
Thank you
This is because:
the value of %{#parameters.action} is an array, not a single value, and
the value will be type-converted to a number (not sure why; need to look in to that)
The correct expression would be:
<s:if test="%{#parameters.action[0] == 1}">YES 1</s:if><s:else>NOT 1</s:else>
The correct expression would be:
<s:if test="#parameters.action[0] == 1">YES 1</s:if><s:else>NOT 1</s:else>
The request parameters is a map of [Strinf, String[]], So you have to access it like above
Can someone please tell me how to convert this to razor view syntax?
<%= ViewData.Model.Firms.Count > 0 ? Html.Pager(ViewData.Model.Firms.PageSize, ViewData.Model.Firms.PageNumber, ViewData.Model.Firms.TotalItemCount) : string.Empty%>
thanks for help in advance.
#if (Model.Firms.Count > 0)
{
#Html.Pager(
Model.Firms.PageSize,
Model.Firms.PageNumber,
Model.Firms.TotalItemCount
)
}
and if you want one liners:
#MvcHtmlString.Create(
Model.Firms.Count > 0
? Html.Pager(
Model.Firms.PageSize,
Model.Firms.PageNumber,
Model.Firms.TotalItemCount
).ToHtmlString()
: string.Empty
)
but personally I find the first far more readable.
You may want to simply make a helper instead that will take care of that logic, so your view can simply call #PagerTable(Model.Firms) which will figure out to write an empty string or call Html.Pager for you.