CODEWITHSUNDEEP
pythonarrayslist
DynamicQ
DynamicQ

Reputation: 135

Python - Iterating through list of lists

I have a list like;

list=[['1,2,3'], ['1,2'], ['1,2,3'], [1.0], [5.0]]

I would like to iterate through it to obtain the index value for each element, something like this;

orig_list=[1,2,3,1,2,1,2,3,1,5]
index_list=[1,1,1,2,2,3,3,3,4,5]

(with indexes starting at 1)

Upvotes: 0

Views: 5034

Answers (3)

J. Goedhart
J. Goedhart

Reputation: 209

list_=[['1,2,3'], ['1,2'], ['1,2,3'], [1.0], [5.0]]

orig_list = []
index_list = []
for x in list_:
    for y in x.split(","): #You can make a list out of a string with split functions.
        index_list.append(list_.index(x)+1)
        orig_list.append(float(y)) #Because you have floats and int in the strings I would convert them both to float.

Upvotes: 0

Jean-François Fabre
Jean-François Fabre

Reputation: 140307

Your data model is a bit strange. Lists containing only one element, being string or float. My answer applies to that strange case.

l=[['1,2,3'], ['1,2'], ['1,2,3'], [1.0], [5.0]]

orig_list=[]
index_list=[]

for i,item in enumerate(l,1):
    if isinstance(item[0],str):
        toks = [int(x) for x in item[0].split(",")]
        orig_list+=toks
        index_list+=[i]*len(toks)
    else:
        orig_list.append(int(item[0]))
        index_list.append(i)

print(orig_list)
print(index_list)

results in:

[1, 2, 3, 1, 2, 1, 2, 3, 1, 5]
[1, 1, 1, 2, 2, 3, 3, 3, 4, 5]

enumerate gives you the index (start at 1). Depending on the type, either split + convert to int, or just convert to float. And create a list of the same index, or just append the current index.

Upvotes: 0

Joshua Nixon
Joshua Nixon

Reputation: 1425

list_=[['1,2,3'], ['1,2'], ['1,2,3'], [1.0], [5.0]]

for x in list_:
    index_ = list_.index(x)

for x in list_:
    for y in x:
        index_ = list_.index(y)

Ii this what you was asking?

EDIT: if your index needs to start at one then simply + 1 to each index

indexs = [list_.index(x) for x in list_]

Upvotes: 1

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