Can anyone tell me why the file content disappears whenever I try to save my modifications in Python?

Question

Can anyone tell me why the file content disappears whenever I try to save my modifications in Python?

In my file test_final.txt, I have a collection of simple words and sentences that I want to shuffle using the shuffle method. However, when I implement the code, it empties out my test_final.txt. Additionally, I am struggling to understand why the Shuffle method is not working as expected.

import random
import re 
import sys
f = open("test_final.txt", "r")
print(f.read())

pattern = r"([a-zA-Z]+) (\d+)"
listOfWords = re.findall(pattern, 'f')
print("Result: ", listOfWords)

random.Random(4).shuffle(listOfWords)
print("Shuffled stuff: ", listOfWords)


finalString = ""
for word in listOfWords: 
    finalString = finalString + word + " "
finalString = finalString.strip()
print(finalString)

#Save

with open("test_final.txt", "w", encoding = 'utf-8') as file:

   file.write(finalString)

For instance, if my test_final.txt contains:

my book is still here, the output after shuffling should be something like this still book here is my.

Despite noticing that the issue lies within the save method causing the file to become empty, I am also facing difficulty with the Shuffle method not shuffling the words correctly as desired.

python python-3.x python-requests

Answer 1

Answer №1

There are several issues with your code.

print(f.read())

This line prints the contents to standard output and leaves the file handle at the end of the file. If you try to read anything more from f at this point, you will receive an empty string.

Since you are not storing the lines or generating new ones in the following code (as seen below), it makes sense that nothing is being written to the new file in the end.

mama = r"([a-zA-Z]+) (\d+)"
listOfWords = re.findall(mama, 'f')

This snippet searches for words followed by a space and numbers in the static string 'f', which obviously doesn't contain any spaces or numbers, resulting in the list listOfWords being empty. Were you attempting to read from the variable f instead? However, even if you were, note that findall expects a string as its second argument, not a file handle.

As mentioned by others, leaving f open while overwriting the same file won't work reliably. It's essential to close f before writing to the same file.

The purpose of calling random.Random(4) is unclear, so I'll assume you intended to shuffle the list randomly using an even distribution.

To achieve your goal of having the list of words as separate strings from the file, your current code needs modifications. Simply split the line and add it to your list.

For a potential solution, consider the following revised code snippet:

import random
import re

mama = r"[a-zA-Z]+\d*"

list_of_words = []

with open("test_final.txt", "r", encoding="utf-8") as f:
    for line in f:
        for word in line.rstrip('\n').split():
            if re.match(mama, word):
                list_of_words.append(word)
            else:
                print('# discarding', word)

print("Result: ", list_of_words)

random.shuffle(list_of_words)
print("Shuffled stuff: ", list_of_words)

final_string = " ".join(list_of_words)
print(final_string)

with open("test_final.txt", "w", encoding='utf-8') as file:
   file.write(final_string)

See a demonstration here: https://ideone.com/fBXb8v

Note that the provided code rearranges the file content onto a single line separated by spaces. This could potentially be destructive, so consider keeping each original line on a separate line for stability and repeatability.

Answer 2

There are several issues with your code.

print(f.read())

This line prints the contents to standard output and leaves the file handle at the end of the file. If you try to read anything more from f at this point, you will receive an empty string.

Since you are not storing the lines or generating new ones in the following code (as seen below), it makes sense that nothing is being written to the new file in the end.

mama = r"([a-zA-Z]+) (\d+)"
listOfWords = re.findall(mama, 'f')

This snippet searches for words followed by a space and numbers in the static string 'f', which obviously doesn't contain any spaces or numbers, resulting in the list listOfWords being empty. Were you attempting to read from the variable f instead? However, even if you were, note that findall expects a string as its second argument, not a file handle.

As mentioned by others, leaving f open while overwriting the same file won't work reliably. It's essential to close f before writing to the same file.

The purpose of calling random.Random(4) is unclear, so I'll assume you intended to shuffle the list randomly using an even distribution.

To achieve your goal of having the list of words as separate strings from the file, your current code needs modifications. Simply split the line and add it to your list.

For a potential solution, consider the following revised code snippet:

import random
import re

mama = r"[a-zA-Z]+\d*"

list_of_words = []

with open("test_final.txt", "r", encoding="utf-8") as f:
    for line in f:
        for word in line.rstrip('\n').split():
            if re.match(mama, word):
                list_of_words.append(word)
            else:
                print('# discarding', word)

print("Result: ", list_of_words)

random.shuffle(list_of_words)
print("Shuffled stuff: ", list_of_words)

final_string = " ".join(list_of_words)
print(final_string)

with open("test_final.txt", "w", encoding='utf-8') as file:
   file.write(final_string)

See a demonstration here: https://ideone.com/fBXb8v

Note that the provided code rearranges the file content onto a single line separated by spaces. This could potentially be destructive, so consider keeping each original line on a separate line for stability and repeatability.

Answer 3

Answer №2

In order to save the changes, it is important to properly close the file.

closeFile()

Answer 4

In order to save the changes, it is important to properly close the file.

closeFile()

Answer 5

Answer №3

When starting the script, you should open a file and read its contents. Make sure to properly close it afterwards. Consider using the with statement to handle file opening.

import random
import re 
import sys
with open("test_final.txt", "r", encoding = 'utf-8') as f:
    text = f.read()
    print(text)

pattern = r"([a-zA-Z]+) (\d+)"
list_of_words = re.findall(pattern, 'f')
print("Result: ", list_of_words)

random.Random(4).shuffle(list_of_words)
print("Shuffled content: ", list_of_words)

final_string = ""
for word in list_of_words: 
    final_string = final_string + word + " "
final_string = final_string.strip()
print(final_string)

# Save

with open("test_final.txt", "w", encoding = 'utf-8') as f:
   f.write(final_string)

Answer 6

When starting the script, you should open a file and read its contents. Make sure to properly close it afterwards. Consider using the with statement to handle file opening.

import random
import re 
import sys
with open("test_final.txt", "r", encoding = 'utf-8') as f:
    text = f.read()
    print(text)

pattern = r"([a-zA-Z]+) (\d+)"
list_of_words = re.findall(pattern, 'f')
print("Result: ", list_of_words)

random.Random(4).shuffle(list_of_words)
print("Shuffled content: ", list_of_words)

final_string = ""
for word in list_of_words: 
    final_string = final_string + word + " "
final_string = final_string.strip()
print(final_string)

# Save

with open("test_final.txt", "w", encoding = 'utf-8') as f:
   f.write(final_string)

Answer 7

Answer №4

Attempting to both read and write the same file concurrently is not a viable option. When you open a file for writing, it will erase all existing data in the file and start fresh. You can choose to open a file in append mode if you want new data to be added at the end of the file, but this might not align with your intentions. Typically, if you need to modify a file, it's best to create a new one and then replace the old file with the new version if desired.

Additionally, remember to close the file after you finish reading from it.

Answer 8

Attempting to both read and write the same file concurrently is not a viable option. When you open a file for writing, it will erase all existing data in the file and start fresh. You can choose to open a file in append mode if you want new data to be added at the end of the file, but this might not align with your intentions. Typically, if you need to modify a file, it's best to create a new one and then replace the old file with the new version if desired.

Additionally, remember to close the file after you finish reading from it.

Can anyone tell me why the file content disappears whenever I try to save my modifications in Python?

Answer №1

Answer №2

Answer №3

Answer №4

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