similar to: maths not working (can't get this)

Can''t get this?...I''m close I think, my calculation appears to be working, but.... when i access duration = <%= @enquiry.course_duration %><br> in my final view it''s blank.. course_duration is getting set to null but works for the calculation? controller.. ---------- class EnquiriesController < ApplicationController layout ''welcome''

trying to figure out the bet way to manage pricing in my app and basically the database design. It''s a language school that also offers host family accomodation. They therefore have Courses which have to have the following prices fixed fees ---------- exam fee reg fee recurring fees -------------- price_per_week (1 to 2 weeks) price_per_week (3 to 4 weeks) price_per_week (5 to 6

Hi, I have some values on my webpage displaying like 1.22333333333 2.33333344444 2.33377777777 etc. Here I want to display values upto 2 decimal places correct. i.e, 1.22333333333 should be dislayed as 1.22 2.33333344444 should be dislayed as 2.33 2.33777777777 should be dislayed as 2.34 & so on.... How to do this in ruby????? Is there any function??? Thanx in advance. Prash --

I have checked out the help files, but cannot find details on how to use maths characters in ylab. Instead of m^2, I would like the 2 in superscript, if possible. I would also like to place more padding on the label so that the label is not obscured by the horizontal numbers. y <- 1:10 x <- rnorm(10,50000,2000) plot(x ~ y, ylab = 'Y Label (m^2)', las = 1, type =

I need to have the maths symbol for >= in the legend, and to substitute threshold variable with its value. Somehow, various attempts weren't successful. Please help. threshold <- 0.5 plot(NA, xlab="", ylab="", main="", axes=F, xlim=c(0,1), ylim=c(0,1), xaxs="i", yaxs="i") legend(x=0, y=1, fill=c("orange", "white",

Hi Mrs & Ms "R", A simple maths question that I am trying to resolve with R: I need to calculate the SE from a pvalue and it's beta... How to do this...? Thank you very much and best regards! Georg Ehret, Geneva, Switzerland. [[alternative HTML version deleted]]

Hi, I am not sure if this is just me using R (R-2.3.1 and R-2.4.0) in the wrong way or if there is a more serious bug. I was having problems getting some calculations to add up so I ran the following tests: > (2.34567 - 2.00000) == 0.34567 <------- should be true [1] FALSE > (2.23-2.00) == 0.23 <------- should be true [1] FALSE > 4-2==2 [1] TRUE > (4-2)==2 [1] TRUE >

The document R-exts contains the following example of using mathematics in R documentation. \deqn{p(x) = {\lambda^x\ \frac{e^{-\lambda}}{x!}} {p(x) = lambda^x exp(-lambda)/x!} There is a syntax error in there, but that's not my point. The problem is that using "R CMD Rd2dvi" I find that putting the alternate forms of the equation on top of each other doesn't work.

hi guys im playing with RoR with the environment of rails 3 ruby 1.9 i got stuck in nil can''t be coerced into BigDecimal error i need to get the total cost of the products inside the cart i know where the problem is(i think) but i almost did every thing cart/show.html.rb <div class="cart_title" >Your Cart</div> <table> <% for item in

I''m doing the depot example in the Agle Web development book. I''m getting this error: "undefined method `product'' for #<BigDecimal:331ce70,''0.21E1'',8(8)> " "Extracted source (around line #9): 8: for item in @items 9: product = item.product 10: -%> 11: <tr> 12: <td><%= item.product%></td>"

I want to use something similar to the following: @total_price += { product.price <> nil ? product.price : 0.0 } This fails in rails with a "nil can''t be coerced into Float" error. What is the (most) correct way to do this? On a related issue, what is the significance of the value 40 following "cart.rb" in the trace snippet below? The entire class file

Given this code (which renders rjs), I''m faced with the fixture- driven way of spec-ing or mocking. How the heck to you mock this so the code at line (2) and (4) work right? I''m still struggling with mocks but it seems like this can be done. Forgive the naivety of this question. 1. def change_quantity 2. @line_item = LineItem.find_by_id(params[:id]) 3. unless

In the Agile Rails tutorial I am revisiting building a cart. I have followed the steps given in the book to create the class ''Cart'' thus: class Cart attr_reader :items attr_reader :total_price def add_product(product) @items << LineItem.for_product(product) @total_price += product.price end def initialize @items = [] @total_price = 0.0 end

Hello all. I have the following code (taken from the depot tutorial then modified) def add_dish( dish, type, qnty ) item = @items.find {|i| i.dish_id == dish.id && i.type == type } if item item.quantity += qnty.to_i else if type == ''Fresh'' item = Fresh.for_dish(dish) else item = Frozen.for_dish(dish) end

I want to modify and update the items in the Depot - "display_cart". Since the cart is in a session, its a little hard to get at the data. I just want to create a way to change quantities, prices and recalculate. Has someone done this, and could you point me to the right direction. Thanks Chas -- Posted via http://www.ruby-forum.com/.

Hello all, I would like to be able to update the "amount" of a certain item in me order list. The problem I run into is how to define the text_field element. @order is the current order, which has_many :order_item which in turn belongs_to :order. order_item has a field "amount" which should be modified... What I tried is this below, but I get a undefined method

When I run the unit testing code in Unit Testing Models chapter of the Agile Rails book, I get the following error: $ ruby test/unit/cart_test.rb Loaded suite test/unit/cart_test Started F. Finished in 0.21806 seconds. 1) Failure: test_add_duplicate_product(CartTest) [test/unit/cart_test.rb:22]: <4690> expected but was <3579>. 2 tests, 3 assertions, 1 failures, 0 errors require

Hello, I am veeeery new to rails and also to ruby. I have 2 books here on my desk and try to go through it. The first book is "Agile Webdevelopment with Rails" and I have trouble with the following code which I have from the book. I cant get it working. I searched a lot on google - and also on the erata pages of the book publisher but without any luck. I hope someone can help me.

hi, i''ve been cracking my head on this one for a while and would be humbly grateful for any pointers i''m working through Agile Web Devopment w Rails and, in the depot example have created the cart class for session handling, but am getting the following error, which suggests the @items variable is not being populated with any data from LineItem NoMethodError (You have a

I''m working on building the shopping cart in the Depot tutorial in the Agile Web Development book. I''m at the part (about page 80) where you build the ability to add items to the cart. I''m able to get to /store/display_cart/ and it seems items are being added, but if I just click on a link to add an item (/store/add_to_cart/2) it gives me this: NoMethodError in