CODEWITHSUNDEEP
pythondictionary
Hayley van Waas
Hayley van Waas

Reputation: 439

How to call an item from a dictionary in python?

So I have a dictionary which consists of a number and its definition is the corresponding element on the periodic table.

I have built up the dictionary like this:

for line in open("periodic_table.txt"):
    temp.append(line.rstrip())

for t in temp:
    if t[1] != " ":
        elements[x] = t[3:]
    else:
        elements[x] = t[2:]
    x += 1

I know that every element is in table because I ask the program to print the dictionary. The point of this is that the user enters a number or element name and the number and name are both printed like this:

while count == 0:
    check = 0
    line = input("Enter element number or element name: ")
    if line == "":
        count = count + 1
        break
    for key,value in elements.items():
        if line == value:
            print ("Element number for",line,"is",key)
            check = 1
            break
        if line.isdigit():
            if int(line) <= 118 and int(line) > 0:
                print ("Element number",line, "is",elements[int(line)])
                check = 1
                break
    if check == 0:
        print ("That's not an element!")

This works for every element except the last one, Ununoctium, in the dictionary. When the user enters 118 this element is printed, but if they enter 'ununoctium' then the program says "That is not an element!". Why is this and how do I fix it?

Thanks in advance

Upvotes: 0

Views: 1716

Answers (2)

Hans Then
Hans Then

Reputation: 11322

It is much easier to have python do the lookup for you. Ignoring empty lines for now:

elements = []
for line in open("periodic_table.txt"):
    elements.append(line[3:])

You can then do a lookup like this:

if answer.isdigit():
    print elements[int(answer)]
else:
    print elements.index(answer)

Upvotes: 2

doctorlove
doctorlove

Reputation: 19252

I suspect this is a case sensitive issue.
Changing 

if line == value:

to

if line.lower() == value.lower():

would solve that problem.
While you are there, why have the if inside the for loop? You could check that first, and then don't need the break

if line.isdigit():
    if int(line) <= 118 and int(line) > 0:
        print ("Element number",line, "is",elements[int(line)])
        check = 1 
        #<-------- break no longer required
else:
    #for loop as above

Upvotes: 2

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