From: shawn bright <nephish@...>
Date: 2006-12-22T06:47:33+09:00
Subject: prob with each_with_index

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lo there all,

i am having a problem making each_with_index do what i need it to do.
the issue is...

i need to evaluate the gpm of a flow sensor.
we are skipping over three database entries to get the values.
difference in value / difference in time = gpm. ok, easy enough.

but this code

@flow_sensor.flow_hits.each_with_index do |hit, i|
          if i > 4 # start with 3rd hit in db
              time_diff = hit[i].date_time.to_i - hit[i-3].date_time.to_i
              value_diff = hit[i].value - hit[i-3].value
              min = time_diff / 60
              val = value_diff / min
              plots.push(val)
              times.push(hit[i].date_time)
          end
        end

is giving me a nil value evaluating nil.date_time

this is for a rails app by the way.

i know i have the models set up right, because other functions are working.
thats why i think my structure is wrong.

thanks.

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