Python delete line in file without loading complete file смотреть онлайн

Deleting a line from a file in Python without loading the complete file into memory can be achieved by reading the file line by line and selectively writing the lines you want to keep to a new file. Here's a step-by-step tutorial with code examples to help you accomplish this task:
Step 1: Open the File
First, you need to open the input file for reading and the output file for writing the modified content. Make sure to open both files in the appropriate mode. In this example, we'll use the context manager with to handle file closing automatically.
Replace 'input.txt' and 'output.txt' with the paths to your input and output files.
Step 2: Identify the Line to Delete
You'll need to specify the line number or some criteria to identify the line you want to delete. For example, you can delete a line if it contains a specific keyword or if it's at a particular line number.
Step 3: Copy Lines to the Output File
Iterate through the lines in the input file and copy them to the output file, skipping the line you want to delete.
Here's an example of how to delete a line that contains a specific keyword:
This code reads each line from the input file and writes it to the output file if it doesn't contain the "delete_this_line" keyword. This effectively deletes all lines containing that keyword.
If you want to delete a line at a specific line number, you can use a counter to keep track of the line number and skip the line you want to delete.
Step 4: Close the Files
Make sure to close both files to save the changes.
However, since we're using the with statement, the files will be automatically closed when the block is exited, so you don't need to explicitly call close().
Full Example:
Here's the complete example that deletes lines containing a specific keyword:
This code will create a new file (output.txt) with the specified lines deleted. Make sure to replace 'input.txt' with the path to your input file and adjust the delete_keyword as needed for your specific use case.
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