How can I read a text file one line at a time in Python?

Use a with statement and loop over the open file. Replace sample.txt with the path to your file. This example assumes it contains a few lines of ordinary text:

with open("sample.txt", "r") as file:
    for line in file:
        print(line, end="")

The loop handles a line on each pass. A line read from a text file normally still has its newline character, and in text mode Python translates platform-specific line endings to \n. [S1] The end="" argument prevents print from adding another newline when the line already has one.

Remove only newline characters at the end with rstrip("\n"):

with open("sample.txt", "r") as file:
    for line in file:
        text = line.rstrip("\n")
        print(repr(text))

If a line contains hello followed by a newline, text remains hello , including its spaces. Avoid plain strip() when those spaces matter, because it removes surrounding whitespace too. Text mode translates platform-specific line endings to \n, so removing that ending does not require removing arbitrary whitespace. [S1] repr makes spaces easier to see in this demonstration; omit it if you do not need that view.

A loop lets you handle lines as they are read. By contrast, read() returns the entire file contents as one string. [S1] For a small file, either approach may suit your task; the loop is useful when your code should work with separate lines rather than one string containing all the contents.

For example, assume sample.txt contains red, blue, and green, each on its own line:

with open("sample.txt", "r") as file:
    for line in file:
        color = line.rstrip("\n")
        print(f"Color: {color}")

The output is:

Color: red
Color: blue
Color: green

This shows the pattern; it does not establish a memory limit or guarantee a speed improvement for a particular file or program.

Change the filename and put your processing inside the loop:

with open("sample.txt", "r") as file:
    for line in file:
        text = line.rstrip("\n")
        # Do something with text, such as print(text)

If output seems to have blank lines, check whether the line already includes its ending before printing: print(line) can add another newline, while print(line, end="") does not add one. If spaces seem to disappear, check that you used rstrip("\n") rather than strip(). The documented behavior covers newline handling in text mode, but it cannot tell you what is in your particular file. Inspect a small sample if you need to check its contents. [S1]