Remove partial duplicate tuples in a list based on condition-CodePudding

I have a list of tuples like this:

mylist = [
    ('Apple', 'Pass'),
    ('Banana', 'Fail'),
    ('Orange', 'Pass'),
    ('Apple', 'Fail')
]

I want to remove tuple ('Apple', 'Fail') as I have ('Apple', 'Pass'), meaning remove tuple which has Fail if another tuple has Pass for Apple and so on, so the new list looks like this:

newList = [
    ('Apple', 'Pass'),
    ('Banana', 'Fail'), 
    ('Orange', 'Pass')
]

How would I do this?

CodePudding user response：

Use:

# create a set to search for tuples that has Pass
pass_tuples = {e for e, s in mylist if s == 'Pass'}

# keep tuples that are Pass or doesn't have a Pass
newList = [(e, s) for e, s in mylist if s == 'Pass' or e not in pass_tuples]
print(newList)

Output

[('Apple', 'Pass'), ('Banana', 'Fail'), ('Orange', 'Pass')]

Basically you want to keep the elements in newList that are Pass or that doesn't have a Pass.

Note: The time complexity of this approach is expected O(n).

CodePudding user response：

# your code goes here
mylist = [
    ('Apple', 'Pass'),
    ('Banana', 'Fail'),
    ('Orange', 'Pass'),
    ('Apple', 'Fail')
]

result = {}
for a, b in mylist:
    if a not in result:
        result[a] = b
    else:
        if result[a] =='Fail' and b=='Pass':
            result[a] = b

mylist =  list(result.items() )
print(mylist)

output

[('Apple', 'Pass'), ('Banana', 'Fail'), ('Orange', 'Pass')]

CodePudding user response：

#create 2 different sets for each fail and pass...

setForPass = set() setForFail = set()

for i in mylist:
    if i[1] == 'Pass':
        setForPass.add(i[0])
for i in mylist:
    if i[1] == 'Fail':
        if i[0] in setForPass:
            mylist.remove(i)

output = [('Apple','Pass'), ('Banana','Fail'), ('Orange','Pass')]

CodePudding user response：

You can use the key-value pairs to build a dict, and use the max function to overwrite the current value of a key if the new value is greater (since Pass is greater than Fail lexicographically; otherwise use a key function). Convert the dict items back to a list of tuples for output:

d = {}
for k, v in mylist:
    d[k] = max(v, d.get(k, v))
newList = list(d.items())

Demo: https://replit.com/@blhsing/DiligentOverjoyedPlane