CODEWITHSUNDEEP
pythonlistloopsiteration
Sator
Sator

Reputation: 776

Populate list of list with conditions

I have a list of list1 listoflist = [[],[],[],[],[]] and want to populate it with data from this function:

def _execute():
    while True:
        user_input = input("type in: ")
        return user_input

What I'm trying to do is to insert data from the input function into the first column, like:

input = 1
[[1],[],[],[],[]]
input = 2
[[1,2],[],[],[],[]]

If the first column length is bigger than 2, then switch to the next column until the last one.

So far I managed to insert data into the first column but it inserts the return value from the input function two times in the first column:

def insertdata(data):
    for i in range(len(listoflist)):
        if len(listoflist[0]) < 2:
            listoflist[0].append(data)

        else:
            print(listoflist)
            break


insertdata(_execute())



# output
type in: 1
[['1', '1'], [], [], [], []]

Do I need to do this operation with indexing ?

1: More like a list of pairs, since the inner list can only store two values.

Upvotes: 1

Views: 129

Answers (3)

RMPR
RMPR

Reputation: 3511

You can put while True out of the _execute() function (every time you return, the while is bypassed) and keep a flag to tell if your data was added or not, additionally, check the boundaries to avoid index errors:

listoflist = [[], [], [], [], []]

def _execute():
    user_input = input("type in: ")
    return user_input

def insertdata(data):
    data_added = False
    i, n = 0, len(listoflist)
    while not data_added and i < n:
        if len(listoflist[i]) < 2:
            listoflist[i].append(data)
            data_added = True
        else:
            i += 1
    if i == n:
        print("\n The list is full, No more elements will be added \n")

while True:
    insertdata(_execute())
    print(listoflist)

Upvotes: 2

po.pe
po.pe

Reputation: 1162

Maybe it's there for another reason, but the while True in your _execute() isn't needed as input is blocking. Further I justed commented what your codeblock is doing

def insertdata(data):
    for i in range(len(listoflist)): #execute the following code for the amount of lists in listoflist, namely 5 times
        if len(listoflist[0]) < 2: #if you have less than 2 elements in the first element of listoflist
            listoflist[0].append(data) # append data to the first element

        else:
            print(listoflist)
            break

for a correct function, see RMPR's answer.

Upvotes: 1

rdas
rdas

Reputation: 21275

You just need to find the first list in the list of lists with space to handle the user input. After adding the user input, you can just return - there is nothing else to do. You are getting the double addition because the append() is in a for-loop

You should also handle the case when no more elements can be added:

listoflist = [[],[],[],[],[]]

def _execute():
    while True:
        user_input = input("type in: ")
        return user_input

def insertdata(data):
    for l in listoflist:
        if len(l) < 2:
            l.append(data)
            return
    else:
        print("no more space")


while True:
    insertdata(_execute())
    print(listoflist)

Output:

type in: 1
[['1'], [], [], [], []]
type in: 1
[['1', '1'], [], [], [], []]
type in: 1
[['1', '1'], ['1'], [], [], []]
type in: 1
[['1', '1'], ['1', '1'], [], [], []]
type in: 1
[['1', '1'], ['1', '1'], ['1'], [], []]
type in: 1
[['1', '1'], ['1', '1'], ['1', '1'], [], []]
type in: 1
[['1', '1'], ['1', '1'], ['1', '1'], ['1'], []]
type in: 1
[['1', '1'], ['1', '1'], ['1', '1'], ['1', '1'], []]
type in: 1
[['1', '1'], ['1', '1'], ['1', '1'], ['1', '1'], ['1']]
type in: 1
[['1', '1'], ['1', '1'], ['1', '1'], ['1', '1'], ['1', '1']]
type in: 1
no more space
[['1', '1'], ['1', '1'], ['1', '1'], ['1', '1'], ['1', '1']]

Upvotes: 0

Related Questions