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Efficiently create list of list of list with varying amount of input

I have a .txt file with floating point numbers inside. This file always contains an even number of values which need to be formatted as follows: [[[a,b],[c,d],[e,f]]]
The values always need to be in pairs of two. Even when there are less or more values: [[[a,b], ... [y,z]]]
So it needs to go from this:
3.31497114423 50.803721015, 7.09205325687 50.803721015, 7.09205325687 53.5104033474, 3.31497114423 53.5104033474, 3.31497114423 50.803721015
To this:
[[[3.31497114423,50.803721015],[7.09205325687,50.803721015],[7.09205325687,53.5104033474],[3.31497114423,53.5104033474],[3.31497114423,50.803721015]]]
I have the feeling this can be done fairly easy and efficiënt. The code I have so far works, but is far from efficient...
with open(filename) as f:
for line in f:
footprint = line.strip()
splitted = footprint.split(' ')
list_str = []
for coordinate in splitted:
list_str.append(coordinate.replace(',', ''))
list_floats = [float(x) for x in list_str]
footprint = [list_floats[x:x+2] for x in range(0, len(list_floats), 2)]
return [footprint]
Any help is greatly appreciated!

The split function is very useful in scenarios such as these.
with open(filename) as f:
# Format the string of numbers into a list seperated by commas
new_list = f.read().split(", ")
# For every element in this list, make it a list seperated by space
# Also convert the strings into floats
for i in range(len(new_list)):
new_list[i] = list(map(float, new_list[i].split(" ")))
new_list = [new_list]
The first split converts the code from this
3.31497114423 50.803721015, 7.09205325687 50.803721015, 7.09205325687 53.5104033474, 3.31497114423 53.5104033474, 3.31497114423 50.803721015
To this
['3.31497114423 50.803721015', '7.09205325687 50.803721015', '7.09205325687 53.5104033474', '3.31497114423 53.5104033474', '3.31497114423 50.803721015']
The second split converts that to this
[['3.31497114423', '50.803721015'], ['7.09205325687', '50.803721015'], ['7.09205325687', 53.5104033474'], ['3.31497114423', '53.5104033474'], ['3.31497114423', '50.803721015']]
Then the mapping of the float function converts it to this (the list converts the map object to a list object)
[[3.31497114423, 50.803721015], [7.09205325687, 50.803721015], [7.09205325687, 53.5104033474], [3.31497114423, 53.5104033474], [3.31497114423, 50.803721015]]
The last brackets place the whole thing into another list
[[[3.31497114423, 50.803721015], [7.09205325687, 50.803721015], [7.09205325687, 53.5104033474], [3.31497114423, 53.5104033474], [3.31497114423, 50.803721015]]]

How to turn a list containing strings into a list containing integers (Python)

I am optimizing PyRay (https://github.com/oscr/PyRay) to be a usable Python ray-casting engine, and I am working on a feature that takes a text file and turns it into a list (PyRay uses as a map). But when I use the file as a list, it turns the contents into strings, therefore not usable by PyRay. So my question is: How do I convert a list of strings into integers? Here is my code so far. (I commented the actual code so I can test this)
print("What map file to open?")
mapopen = input(">")
mapload = open(mapopen, "r")
worldMap = [line.split(',') for line in mapload.readlines()]
print(worldMap)
The map file:
1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,
2,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
1,0,2,0,0,3,0,0,0,0,0,0,0,2,3,2,3,0,0,2,
2,0,3,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
1,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,2,
2,3,1,0,0,2,0,0,0,2,3,2,0,0,0,0,0,0,0,1,
1,0,0,0,0,0,0,0,0,1,0,1,0,0,1,2,0,0,0,2,
2,0,0,0,0,0,0,0,0,2,0,2,0,0,2,1,0,0,0,1,
1,0,0,0,0,0,0,0,0,1,3,1,0,0,0,0,0,0,0,2,
2,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
1,0,2,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,2,
2,0,3,0,0,2,0,0,0,0,0,0,0,2,3,2,1,2,0,1,
1,0,0,0,0,3,0,0,0,0,0,0,0,1,0,0,2,0,0,2,
2,3,1,0,0,2,0,0,2,1,3,2,0,2,0,0,3,0,3,1,
1,0,0,0,0,0,0,0,0,3,0,0,0,1,0,0,2,0,0,2,
2,0,0,0,0,0,0,0,0,2,0,0,0,2,3,0,1,2,0,1,
1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,3,0,2,
2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,1,
2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,
Please help me, I have been searching all about and I can't find anything.

try this: Did you want a list of lists? or just one big list?
with open(filename, "r") as txtr:
data = txtr.read()
data = txtr.split("/n") # split into list of strings
data = [ list(map(int, x.split(","))) for x in data]
fourth line splits string into list by removing comma, then appliea int() on each element then turns it into a list. It does this for every element in data. I hope it helps.
Here is for just one large list.
with open(filename, "r") as txtr:
data = txtr.readlines() # remove empty lines in your file!
data = ",".join(data) # turns it into a large string
data = data.split(",") # now you have a list of strings
data = list(map(int, data)) # applies int() to each element in data.

Look into the map built-in function in python.
L=['1', '2', '3']
map = map(int, L)
for el in map:
print(el)
>>> 1
... 2
... 3

As per you question, please find below a way you can change list of strings to list of integers (or integers if you use list index to get the integer value). Hope this helps.
myStrList = ["1","2","\n","3"]
global myNewIntList
myNewIntList = []
for x in myStrList:
if(x != "\n"):
y = int(x)
myNewIntList.append(y)
print(myNewIntList)

How to remove the stuff lists add when writing to textfiles

I need to write a list to a text file named accounts.txt in the following format:
kieranc,conyers,asdsd,pop
ethand,day,sadads,dubstep
However, it ends up like the following with brackets:
['kieranc', 'conyers', 'asdsd', 'pop\n']['ethand', 'day', 'sadads', 'dubstep']
Here is my code (accreplace is a list):
accreplace = [['kieranc', 'conyers', 'asdsd', 'pop\n'],['ethand', 'day', 'sadads', 'dubstep']]
acc = open("accounts.txt", "w")
for x in accreplace:
acc.write(str(x))

Since each element in accreplace is a list, str(x) doesn't help. It just adds quotes around it. To print the list in proper format use the code below:
for x in accreplace:
acc.write(",".join([str(l) for l in x]))
This will convert the list items into a string.

Python len not working

In the code below, I am trying to use len(list) to count the number of strings in an array in each of the tags variables from the while loop. When i did a sample list parameter on the bottom, list2, it printed 5 which works, but when i did it with my real data,it was counting the characters in the array, not the number of strings. I need help figuring out why that is and i am new to python so the simplest way possible please!
#!/usr/bin/python
import json
import csv
from pprint import pprint
with open('data.json') as data_file:
data = json.load(data_file)
#pprint(data)
# calc number of alert records in json file
x = len(data['alerts'])
count = 0
while (count < x):
tags = str(data['alerts'][count] ['tags']).replace("u\"","\"").replace("u\'","\'")
list = "[" + tags.strip('[]') + "]"
print list
print len(list)
count=count+1
list2 = ['redi', 'asd', 'rrr', 'www', 'qqq']
print len(list2)

Your list construction list = "[" + tags.strip('[]') + "]" creates a string, not a list. So yes, len works, it counts the characters in your string.
Your tags construction looks a bit off, you have a dictionary of data (data['alerts']) which you then convert to string, and strip of the '[]'. Why don't use just get the value itself?
Also list is a horrible name for your variable. This possible clashes with internal values.

list = "[" + tags.strip('[]') + "]"
print list
print len(list)
Ironically, list is a string, not a list. That's why calling len on it "was counting the characters in the array"

you need to make sure that your variable is a list rather than a str,
try:
print(type(yourList))
if it shows that it is a str, then try this:
len(list[yourList)
hope this answers your question
and when you want to establish a list variable, try this:
myList = []
for blah in blahblah:
myList.append(blah)
I think these definitely solved your problem, so I hope you noticed this part.

How do you split a single python list element into several independent list elements?

I have a .txt file that reads exactly like this:
0,Hello,01,Cooking,02,Biking,13,My Hawaii Vacation,14,Freezing weather in Iowa,0
The code I have so far is:
a = open('wiki.txt','r')
ar = a.readlines()
biglistA = map(lambda each:each.strip('\n'), ar)
Which gives me output of:
['0,Hello,0', '1,Cooking,0', '2,Biking,1', '3,My Hawaii Vacation,1', '4,Freezing weather in Iowa,0']
I need to get this to look like:
[['0','Hello','0'], ['1','Cooking','0'], ['2','Biking','1'], ['3','My Hawaii Vacation','1'], ['4','Freezing weather in Iowa','0']]
The final product needs to be a nested list with each element being referenced, i.e:
print newlist[1][1]
'Cooking'
That is the desired output. If anyone can help it would be greatly appreciated!

It looks to me like you need something like:
with open('wiki.txt') as fin:
bigListA = [ line.strip().split(',') for line in fin ]

A strange requirement. I guess a regex would be the best bet:
import re
with open('wiki.txt') as f:
s = f.read()
newlist = [triple.split(',') for triple in re.findall(r'\d,.*?,\d', s)]
Or, continuing on from where you were at already, just apply a list comprehension like:
newlist = [x.split(',') for x in biglistA]