# How to read a file line-by-line in Python?

To read a file line-by-line in Python, you can use the following approach:

```python
with open('file.txt') as f:
    for line in f:
        print(line)
```

This will open the file, read each line in the file, and then print the line. The `with` statement is used to open the file and automatically close it when the block of code inside the `with` statement is completed.

If you want to do something more complex with each line, you can use a loop to iterate over the lines in the file and process each line as needed.

```python
with open('file.txt') as f:
    for line in f:
        # do something with the line
        process_line(line)
```

You can also read all the lines of a file into a list and then process the lines using the list methods.

```python
with open('file.txt') as f:
    lines = f.readlines()

# do something with the lines
for line in lines:
    process_line(line)
```

Both of these approaches have the advantage of reading the file one line at a time, which can be useful for very large files that don't fit in memory.