Write file with specific number of columns

Question

I need to write a text document that has a specific number of columns (in this case there are always 16). The way I found to make this happen was: check which is the len of the array (list) where the values I want are and divide by 16, getting the number of rows enough to equate to 16 columns precisely. Surely there is a much more correct way to optimize this process. Another question I take advantage of to ask is (because I really don't know how to do it): how to write in 16 columns and always leave with an indentation equivalent to the largest number of that array (i.e.: 8500 = 4 characters = 4 spaces). Something like this:

Example

Here is my code:

f = open('Questions.txt','r')

my_list = [line.split(',')[0]  for line in f]

ff = open('Questions_new.txt','w')

i=0
x=len(my_list)

rows = int(round(len(my_list)//16))

for i in range(rows):
   row = my_list [i::rows]
   ff.write(' '.join(str(x) for x in row)+'\n')

The use of line.split is because I am extracting from a text document (example below) all characters of a text document until a comma is found:

1213,4214 12312

13,1231 123

45,343

and he just keeps the information for me:

1213

13

45

If someone could help I would be thankful.

Answer 1

To answer your first question regarding the number of rows, I think your method is quite efficient. An alternative way to structure this includes:

• Have a while loop which reads in a new value from the text file in every iteration. Inside the while loop, keep a counter for n_rows and n_cols.
  • Write the new value into the output to output[n_rows][n_cols] to right in the current row
  • If n_cols == 16, increment n_row++

Regarding your second question, you could:

• do a first pass of reading in all the values, storing them into an array
• when adding the new value to the array, compare the number of digits against the current max number of digits
• Copy the values from the array into the output text file, padding up to the max number of digits