Appending the elements of a list after importing them from a file in Python

Question

Appending the elements of a list after importing them from a file in Python

My goal is to read elements from a file, add each line to print its output. However, I have been unsuccessful in my attempts so far. For example, if I try to access a certain number:

with open('test.txt', 'r') as f:
    for line in f:
         for s in line.split(' '):
             num = int(s)
             print(num[1])

TypeError: 'int' object is not subscriptable

I also tried another approach by reading each line, storing it in a list, and then converting it into an integer to use them later:

with open('test.txt', 'r') as f:
    filer = f.readlines()
    filer = map(int, filer)
    print(filer[1])

Unfortunately, this method also resulted in an error:

TypeError: 'map' object is not subscriptable

As a beginner in Python, I am still learning and trying to figure out the best way to achieve my goals.

python python-3.x

Answer 1

Answer №1

When using Python 3.x, the map function will return a map object that does not support indexing.

If you need to access elements in the map object, you can convert it to a list using the built-in function list:

with open('test.txt', 'r') as f:
    filer = f.readlines()
    filer = list(map(int, filer))
    print(filer[1])

Another option is to use a list comprehension for a more concise approach:

with open('test.txt', 'r') as f:
    filer = f.readlines()
    filer = [int(x) for x in filer]
    print(filer[1])

Additionally, it's worth mentioning that the open function in Python defaults to read-mode, so you can omit the mode argument:

with open('test.txt') as f:

Nevertheless, some developers prefer to include the explicit 'r' for clarity, so the choice is yours to make.

Answer 2

When using Python 3.x, the map function will return a map object that does not support indexing.

If you need to access elements in the map object, you can convert it to a list using the built-in function list:

with open('test.txt', 'r') as f:
    filer = f.readlines()
    filer = list(map(int, filer))
    print(filer[1])

Another option is to use a list comprehension for a more concise approach:

with open('test.txt', 'r') as f:
    filer = f.readlines()
    filer = [int(x) for x in filer]
    print(filer[1])

Additionally, it's worth mentioning that the open function in Python defaults to read-mode, so you can omit the mode argument:

with open('test.txt') as f:

Nevertheless, some developers prefer to include the explicit 'r' for clarity, so the choice is yours to make.

Answer 3

Answer №2

It appears that you are saving your data as a single number, but it would be better to use a list for better organization. Give this code a try:

with open('data.txt', 'r') as file:
    dataList = []
    for item in file:
         for element in item.split(' '):
             dataList.append(int(element))       
             print(dataList[-1])

Answer 4

It appears that you are saving your data as a single number, but it would be better to use a list for better organization. Give this code a try:

with open('data.txt', 'r') as file:
    dataList = []
    for item in file:
         for element in item.split(' '):
             dataList.append(int(element))       
             print(dataList[-1])

Answer 5

Answer №3

If you only need to access one number at a time, consider modifying the code from print(num[1]) to simply print(num).

Answer 6

If you only need to access one number at a time, consider modifying the code from print(num[1]) to simply print(num).

Appending the elements of a list after importing them from a file in Python

Answer №1

Answer №2

Answer №3

Similar questions

Tips for narrowing down a sqlalchemy query based on a specific field within the most recent child entry

"Decoding Hydra: What's the Best Way to Represent 'None' in Configuration Files

What is the process for loading a webpage into another webpage with google app engine?

Challenge with Jinja2 formatting

How can one best tackle the solution of a differential equation at each interval of time?

Looking to access nasdaq.com using both Python and Node.js

Merge together all the columns within a dataframe

Eliminate redundant rows by comparing assorted columns and conditions within Python

Using the key from a nested CSV file as the primary key in Python

The problem with importing a pre-defined Selenium function in the browser

What is the best way to exchange configuration data among Javascript, Python, and CSS within my Django application?

How can you pull information from Finnhub.io? (incorporating JSON into a pandas data table)

Running Anaconda on an Ubuntu system with 32-bit architecture

Detect Peaks in a Graph Using Python

Visualizing data with Matplotlib: Histogram displaying frequency in thousands

Is it possible to utilize a yyyy-mm-w format when plotting datetime data?

Transforming data in Pandas by consolidating multiple columns into a single column

Adding a basic function within a Django HTML template can enhance the functionality and flexibility

I encountered a PermissionError while trying to log in as an administrator

I am encountering a 404 error when attempting to make a GET request for a file located in the same directory