从列表列表中的列表中删除字符串

Question

What I'm trying to achieve here in a small local test is to iterate over an array of strings, which are basically arrays of strings inside a parent array.

I'm trying to achieve the following...

• 1) Get the first array in the parent array
• 2) Get the rest of the list without the one taken
• 3) Iterate through the taken array, so I take each of the strings
• 4) Look for each string taken in all of the rest of the arrays
• 5) If found, remove it from the array

So far I've tried the following, but I'm struggling with an error that I don't know where it does come from...

lines = map(lambda l: str.replace(l, "\n", ""),
            list(open("PATH", 'r')))

splitLines = map(lambda l: l.split(','), lines)

for line in splitLines:
    for keyword in line:
        print(list(splitLines).remove(keyword))

But I'm getting the following error...

ValueError: list.remove(x): x not in list

Which isn't true as 'x' isn't a string included in any of the given test arrays.

SAMPLE INPUT (Comma separated lines in a text file, so I get an array of strings per line):

[['a', 'b', 'c'], ['e', 'f', 'g'], ['b', 'q', 'a']]

SAMPLE OUTPUT:

[['a', 'b', 'c'], ['e', 'f', 'g'], ['q']]

Answer 1

You can keep track of previously seen strings using a set for fast lookups, and using a simple list comprehension to add elements not found in the previously seen set .

prev = set()
final = []
for i in x:
  final.append([j for j in i if j not in prev])
  prev = prev.union(set(i))

print(final)

Output:

[['a', 'b', 'c'], ['e', 'f', 'g'], ['q']]

Answer 2

inputlist = [['a', 'b', 'c'], ['e', 'f', 'g'], ['b', 'q', 'a']]
scanned=[]

res=[]
for i in inputlist:
    temp=[]
    for j in i:
        if j in scanned:
            pass
        else:
            scanned.append(j)
            temp.append(j)
    res.append(temp)

---

[['a', 'b', 'c'], ['e', 'f', 'g'], ['q']]