使用 python 中的 txt 文件中的数据进行计算

Question

Detailed:

I have a set of 200 or so values in a txt file and I want to select the first value b[0] and then go through the list from [1] to [199] and add them together.

So, [0]+[1]

if that's not equal to a certain number, then it would go to the next term ie [0]+[2] etc etc until it's gone through every term. Once it's done that it will increase b[0] to b[1] and then goes through all the values again

Step by step:

1. Select first number in list.
2. Add that number to the next number
3. Check if that equals a number
4. If it doesn't, go to next term and add to first term
5. Iterate through these until you've gone through all terms/ found a value which adds to target value
6. If gone through all values, then go to the next term for the starting add value and continue

I couldn't get it to work, if anyone can maybe provide a solution or give some advice? Much appreciated. I've tried looking at videos and other stack overflow problems but I still didn't get anywhere. Maybe I missed something, let me know: Thank you! :)

I've attempted it but gotten stuck. This is my code so far:

b = open("data.txt", "r")
data_file = open("data.txt", "r")

for i, line in enumerate(data_file):
    if (i+b)>2020 or (i+b)<2020:
        b=b+1
    else:
        print(i+b)
        print(i*b)

Error:

Traceback (most recent call last):
  File "c:\Users\███\Desktop\ch1.py", line 11, in <module>
    if (i+b)>2020 or (i+b)<2020:
TypeError: unsupported operand type(s) for +: 'int' and '_io.TextIOWrapper'
PS C:\Users\███\Desktop>

Answer 1

Here are some things that you can fix.

You can't add the file object b to the integer i. You have to convert the lines to int by using something like:

integer_in_line = int(line.strip())

Also you have opened the same file twice in read mode with:

b = open("data.txt", "r")
data_file = open("data.txt", "r")

Opening it once is enough.

Make sure that you close the file after you used it:

data_file.close()

To compare each number in the list with each other number in the list you'll need to use a double for loop. Maybe this works for you:

certain_number = 2020

data_file = open("data.txt", "r")
ints = [int(line.strip()) for line in data_file] # make a list of all integers in the file
for i, number_at_i in enumerate(ints): # loop over every integer in the list
    for j, number_at_j in enumerate(ints): # loop over every integer in the list
        if number_at_i + number_at_j == certain_number: # compare the integers to your certain number
            print(f"{number_at_i} + {number_at_j} = {certain_number}")

data_file.close()

Answer 2

I would read the file into an array and then convert it into ints before actually dealing with the problem. files are messy and the less we have to deal with them the better

with open("data.txt", "r") as data_file:
    lines = data_file.readlines() # reads the file into an array
    data_file.close
j = 0 # you could use a better much more terse solution but this is easy to understand
for i in lines: 
    lines[j] = int(i.strip().replace("\n", ""))
    j += 1

i, j = 0
for i in lines: # for every value of i we go through every value of j
    # so it would do x = [0] + [0] , [0] + [1] ... [1] + [0] .....
    for j in lines:
        x = j + i
        if x == 2020:
            print(i * j)

Answer 3

Your problem is the following: The variables b and data_file are not actually the text that you are hoping they are. You should read something about reading text files in python, there are many tutorials on that.

When you call open("path.txt", "r") , the open function returns a file object, not your text. If you want the text from the file, you should either call read or readlines . Also it is important to close your file after reading the content.

data_file = open("data.txt", "r") # b is a file object
text = data_file.read() # text is the actual text in the file in a single string
data_file.close()

Alternatively, you could also read the text into a list of strings, where each string represents one line in the file: lines = data_file.readlines() .

I assume that your "data.txt" file contains one number per line, is that correct? In that case, your lines variable will be a list of the numbers, but they will be strings, not integers or floats. Therefore, you can't simply use them to perform calculation. You would need to call int() on them.

Here is an example how to do it. I assumed that your textfile looks like this (with arbitary numbers):

1
2
3
4
... 

file = open("data.txt", "r")
lines = file.readlines()
file.close()

# This creates a new list where the numbers are actual numbers and not strings
numbers = []
for line in lines:
   numbers.append(int(line))

target_number = 2020
starting_index = 0

found = False
for i in range(starting_index, len(numbers)):
    temp = numbers[i]
    for j in range(i + 1, len(numbers)):
        temp += numbers[j]
        if temp == target_number:
            print(f'Target number reached by adding nubmers from {i} to {j}')
            found = True
            break #This stops the inner loop.
    if found:
        break #This stops the outer loop