我得到一个10位数字，需要用它做这样的事情：
1 * 1stdigit + 2 * 2nddigit + 3 * 3rddigit + ... + 9 * 9thdigit + 1 * 10thdigit = sum
例如，如果数字是9876543210，它将如下所示：
1 * 9 + 2 * 8 + 3 * 7 + 4 * 6 + 5 * 5 + 6 * 4 + 7 * 3 + 8 * 2 + 9 * 1 + 1 * 0
对于我的生活，我无法弄清楚如何做到这一点。所以任何帮助将不胜感激
答案 0 :(得分：1)
你可以在数字的字符串表示上使用GET example
it "renders the #show view" do
food = create(:food)
get :show, params: { id: food.id }
expect(response).to render_template :show
end
CREATE Example
it "redirects to user page of user who uploaded food" do
food_params = FactoryGirl.attributes_for(:food)
post :create, :food => food_params
expect(response).to redirect_to user_path(@user.id)
end
SHOW example
it "assigns the requested food to @food" do
food = create(:food)
get :show, params: { id: food.id }
expect(assigns(:food)).to eq(food)
end
DELETE
it "deletes the food" do
expect{ delete :destroy, id: @food}.to change(Food, :count).by(-1)
end
it "redirects to user page of user who deleted food" do
delete :destroy, id: @food
expect(response).to redirect_to user_path(@user.id)
end
PUT
it "located the requested @food" do
put :update, id: @food, food: FactoryGirl.attributes_for(:food)
expect(assigns(:food)).to eq(@food)
end
it "changes @food's attributes" do
put :update, id: @food,
food: FactoryGirl.attributes_for(:food, title: "Yummers", kind: "Salad")
@food.reload
expect(@food.title).to eq("Yummers")
expect(@food.kind).to eq("Salad")
end
并乘以索引mod 10，从1开始：
enumerate