CODEWITHSUNDEEP
pythonlistpython-3.x
HealYouDown
HealYouDown

Reputation: 156

Python - Adding something to a list only once

my problem is that I only want to add the string "Karte1" once to a list. But right now, the string "Karte1" is adding to a list unlimited times.. Hope u can help me :)

import random

Deck1 = []

def startgame():
    try:
        "Karte1" not in Deck1
        if True:
            Deck1.append("Karte1")
        if False:
            pass
    except:
        pass


while True:
    startgame()
    print(Deck1)

Upvotes: 5

Views: 9084

Answers (3)

arunk2
arunk2

Reputation: 2416

You can use a set data structure rather than a list. A set holds unique values, by default.

From Python Docs

https://docs.python.org/2/library/sets.html

The sets module provides classes for constructing and manipulating unordered collections of unique elements. Common uses include membership testing, removing duplicates from a sequence, and computing standard math operations on sets such as intersection, union, difference, and symmetric difference.

Example

my_set = set([1,2,3,2])
print(my_set)    # prints [1,2,3]

my_set.add(4)
print(my_set)    # prints [1,2,3,4]

my_set.add(3)
print(my_set)    # prints [1,2,3,4]

Upvotes: 2

omri_saadon
omri_saadon

Reputation: 10641

You can use a set if you want unique values.

But in your case just change your code to:

if "Karte1" not in Deck1:
    Deck1.append("Karte1")

EDIT:

Notice that in your while statement you call to the function startgame2, when the name of the function you defined is startgame

Upvotes: 6

Darkpingouin
Darkpingouin

Reputation: 196

The if Truestatement will allways be True, so each time you call the startgame()function it will add it to the Deck

What you probably want to do is :`

if "Karte1" not in Deck1:
     Deck1.append("Karte1")

Upvotes: 0

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