how to loop element for list in python

Question

list=[[AA,'1'] ,[BB,'4'] ,['CC','3']]

I want expand list[0] of count list[1]

Expected output: ['AA','BB','BB','BB','BB','CC','CC','CC']

I try below 2 ways but not works... Please could tell me where i need to fix?

⓵
variableName = []
         for row in rows:
            vName = row[0]
            count = int(row[1])
                          
            result = Counter(vName=count)
            variableName.append(list(result.elements()))

⓶
variableName = []
         for row in rows:
            vName = row[0]
            count = int(row[1])
　　　　　　while count < countRW:
                variableName.append(vName)

You are making it harder than it should be. Try simplifying like: [i for i, n in list1 for _ in range(int(n))]? — Chris
– Chris, Commented Aug 3, 2021 at 9:22
First time i try python thats why i don`t know some keyword.. Thanks for your answer i will try that way — Momo
– Momo, Commented Aug 5, 2021 at 0:34

blhsing · Accepted Answer · 2021-08-03 08:58:55Z

1

Your first approach would work if you construct the Counter object properly by passing a dict object instead of a keyword argument with a fixed name, and if you call list.extend instead to avoid nesting the list:

for row in rows:
    vName = row[0]
    count = int(row[1])
    result = Counter({vName: count})
    variableName.extend(list(result.elements()))

Your second approach would work if you keep decreasing the counter in the while loop and exit the loop when the counter reaches 0:

for row in rows:
    vName = row[0]
    count = int(row[1])
    while count > 0:
        variableName.append(vName)
        count -= 1

answered Aug 3, 2021 at 8:58

blhsing

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Comments

Atanu · Accepted Answer · 2021-08-03 08:58:07Z

1

First of all the list you have given isn't in correct format. It should be likelist1 =[['AA','1'] ,['BB','4'] ,['CC','3']]

After that you can use the output function and pass your desired list as an argument you will get an list in return :

list1 =[['AA','1'] ,['BB','4'] ,['CC','3']]

def output(rows):
    variableName = []
    for row in rows:
        vName = row[0]
        count = int(row[1])
        for num_of_element in range(count):
            variableName.append(vName)
    return variableName

print(output(list1))

edited Aug 3, 2021 at 8:58

answered Aug 3, 2021 at 8:40

Atanu

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2 Comments

Momo Over a year ago

Thanks for quick answer. when i use that i get error "TypeError: 'list' object cannot be interpreted as an integer".

Atanu Over a year ago

I have edited the answer. This time you shouldn't get any Error. Try to understand the code.

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