Finding averages from certain lines of a text file in python

user_17307706 0
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I am trying to gather numbers from a simple text file and compute the average of those numbers. However, I need two separate averages from the text file. The text file would be in this format.

random string
num 1
num 2
random string
random string
num 1
num 2
random string
random string
num 1 
num 2
random string
random string
num 1
num 2
random string

... and so on and so forth, the pattern would always be this way.

I'd need to be able to get the average of all the num1's, then the average of all the num2's separately. The numbers would be integers. What method could I use to do this? Maybe adding them to an array or list and calculating them that way? Or is there another way?

Any guidance or advice would be much appreciated.

text-files python
4 Answers
text = '''random string
1
2
random string
random string
3
4
random string
random string
5
6
random string
random string
7
8
random string'''

You can use regular expression, and get first, and second numbers in the pairs to two different lists, then perform the remaining operations:

first=[]
second=[]
for m in re.finditer(r'\n(\d+)\n(\d+)\n', text):
    first.append(int(m.group(1)))
    second.append(int(m.group(2)))

OUTPUT:

# The values captured from the text string
>>>first, second
([1, 3, 5, 7], [2, 4, 6, 8])
# Average of first values in the pairs
>>> (sum(first)/len(first))
4.0
# Average of second values in the pairs
>>> (sum(second)/len(second))
5.0
user_91363480

start by opening the file then read the first line. Then use a for loop and add all the numbers to a total then divide by the total amount of numbers read.

import os

PATH = os.path.dirname(__file__)

with open(PATH+r"\your_text_file.txt", "r") as file:
    total_first = 0
    total_second = 0
    cardinal = 0   # The cardinal is the number of elements in a set.

    for line in file:   # I know that there is a reccurent pattern in the text file.
        try:
            int(line)
        except ValueError:   # If the line is a string, read the next 2 lines as integers then read a third line and start over.
            cardinal += 1
            total_first += int(file.readline())
            total_second += int(file.readline())
            file.readline()

    average_first = total_first / cardinal
    average_second = total_second / cardinal
user_141135040

You can use regex to extract all the numbers and then work around that.

import re

with open('test.txt') as file:
    s = file.read()
    nums = re.findall(r'\d', s)
    nums = [int(num) for num in nums]
    nums.sort()
    print(nums)

This will give you a list of all integers in your text file in ascending order.

user_157431180

You can use linecache.

import linecache
line = linecache.getline(file.txt, line_number) # Note: first line is 1, not 0

Once you can access any line, calculating the averages is trivial.

user_8397330
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