Use a list or array in Python?
<p>I need to store information for 6 items and their respective length, width and cost values and then work out some values based on user input.</p>

<p>With the help of jcusick, I have now the code below. </p>

<p>I now need help for the items marked in the comments (#).</p>

<p>You do not need to write the complete code - pointing in right direction is perfect. </p>

<p>So far I have:</p>

<pre><code>cost = {}
cost['Themon'] = 450
cost['Larrec'] = 700
cost['Medrec'] = 500
cost['Parallel'] = 825
cost['Suncatch'] = 400
cost['Chantran'] = 975

length = {}
length['Themon'] = 3.2
length['Larrec'] = 3.4
length['Medrec'] = 2.1
length['Parallel'] = 5
length['Suncatch'] = 3
length['Chantran'] = 9

width = {}
width['Themon'] = 2.3
width['Larrec'] = 3
width['Medrec'] = 2
width['Parallel'] = 4
width['Suncatch'] = 3
width['Chantran'] = 6

area = {}
area['Themon'] = 1 # how do i calculate the area (l*w) by referencing the lenght and width dictionary 
area['Larrec'] = 1
area['Medrec'] = 1
area['Parallel'] = 1
area['Suncatch'] = 1
area['Chantran'] = 1

#menu
ans=True
while ans:
    print("""
    Enter 1. to find cheapest garden deck 
    Enter 2. to display the names of garden decks over a certain lenght
    Enter 3. to display the number of garden decks that are available over a certain area
    Enter 4. to quit
    """)
    ans=input("What option would you like? ")
    if ans=="1":
        print (min(cost, key=cost.get))
    elif ans=="2":
        input_length = input("\n Please enter minimum deck length between 2 and 15 metres")
        print # i need to display names of the decks greater than the user input length
    elif ans=="3":
        input_area = input("\n Please enter deck area in metres squared between 4 and 80")
        print # i need to display the number of garden decks that are greater that the user input area
    elif ans=="4":
        print("\n Thank you for using Penny's Decking")
    else:
        print("\n Not a valid choice")
</code></pre>

<p>I would suggest you look into Pandas and implement this more specifically using  DataFrames as they are perfect for what you are doing. Like mentioned by the other guys. Make sure your indentations are formatted correctly. If you don't want to use DataFrames which imho are perfect for what you are doing. I would suggest creating a dictionary of values and referencing them. </p>

python python-3.x