Name of a list changing as I go through a loop

Question

I am trying to make 100 lists with names such as: list1, list2, list3, etc. Essentially what I would like to do is below (although I know it doesn't work I am just not sure why).

num_lists=100

while i < num_lists:
    intial_pressure_{}.format(i) = []
    centerline_temperature_{}.format(i) = []

And then I want to loop through each list inserting data from a file but I am unsure how I can have the name of the list change in that loop. Since I know this won't work.

while i < num_lists:
    initial_pressure_i[0] = value

I'm sure what I'm trying to do is really easy, but my experience with python is only a couple of days. Any help is appreciated. Thanks

Answer 1

Instead of creating 100 list variables, you can create 100 lists inside of a list. Just do:

list_of_lists = [[] for _ in xrange(100)]

Then, you can access lists on your list by doing:

list_of_lists[0] = some_value  # First list
list_of_lists[1] = some_other_value  # Second list
# ... and so on

Answer 2

Welcome to Python!

Reading your comments on what you are trying to do, I suggest ditching your current approach. Select an easier data structure to work with.

Suppose you have a list of files:

files = ['data1.txt', 'data2.txt',...,'dataN.txt']

Now you can loop over those files in turn:

data = {}
for file in files:
   data[file] = {}
   with open(file,'r') as f:
      lines=[int(line.strip()) for line in f]
      data[file]['temps'] = lines[::2]            #even lines just read
      data[file]['pressures'] = lines[1::2]       #odd lines

Then you will have a dict of dict of lists like so:

 {'data1.txt': {'temps': [1, 2, 3,...], 'pressures': [1,2,3,...]},
  'data2.txt': {'temps': [x,y,z,...], 'pressures': [...]},
  ...}

Then you can get your maxes like so:

max(data['data1.txt']['temps'])

Just so you can see what the data will look like, run this:

data = {}
for i in range(100):
    item = 'file' + str(i)
    data[item] = {}
    kind_like_file_of_nums = [float(x) for x in range(10)]
    data[item]['temps'] = kind_like_file_of_nums[0::2]
    data[item]['pres'] = kind_like_file_of_nums[1::2]

print(data)