# Python Write Multiple Lines to File With writelines

> Write single or multiple lines to files in Python using open() with append mode, f.write() with newline characters, or f.writelines() for lists of strings

**URL:** https://sentry.io/answers/write-one-or-more-lines-to-a-file-in-python/

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## The Problem

What is the correct way to write lines to a file in Python?

## The Solution

The standard way to write a single line to a file in Python 3 is as follows:

```python
with open('my_file.txt', 'a') as f:
    f.write('A new line.\n')
```

First, we use a [`with`](https://docs.python.org/3/reference/compound_stmts.html#the-with-statement) statement to wrap our write actions between the file's opening and closing. This is a more succinct and Pythonic way of writing the following:

```python
f = open('my_file.txt', 'a')
f.write('A new line.\n')
f.close()
```

Using `with` means we don't have to remember to close the file after writing to it.

We use Python's [`open()`](https://docs.python.org/3/library/functions.html#open) function to open the file and create a corresponding [file object](https://docs.python.org/3/glossary.html#term-file-object), `f`. The second argument specifies the opening *mode*. Files can be opened in a number of different modes, most commonly `'r'` for reading and `'w'` for writing. The mode we've used here, `'a'`, is short for *append*. It is similar to opening the file for writing, but will ensure that any lines we write are appended to the end of the file. Standard `'w'` writing mode, by contrast, would cause us to overwrite the file from the first line.

With the file open, we call [`f.write()`](https://docs.python.org/3/library/io.html#io.TextIOBase.write) with the line to write. We conclude the line with a newline character, `\n`. You may have heard that line terminators differ between operating systems – Unix-based systems use `\n`, whereas Microsoft Windows uses `\r\n`. Fortunately, Python [abstracts this detail](https://docs.python.org/3/library/os.html#os.linesep) and we can just use `\n` regardless of our operating system.

If we want to write more than one line to our file, there are a few ways to go about it. First, if we know exactly what lines to write, we can use a string with multiple `\n`s, or a multi-line triple-quoted string.

```python
with open('my_file.txt', 'a') as f:
    f.write('A new line.\nA second new line.')
```

```python
with open('my_file.txt', 'a') as f:
    f.write("""A new line
A second new line.""")
```

If we want to write lines from a list, we can use [`f.writelines()`](https://docs.python.org/3/library/io.html#io.IOBase.writelines). Note that `writelines()` does not add line separators automatically, so each string in the list should end with `\n`:

```python
lines = ['A new line.\n', 'A second new line.\n']

with open('my_file.txt', 'a') as f:
    f.writelines(lines)
```

---

*Source: [sentry.io/answers/write-one-or-more-lines-to-a-file-in-python/](https://sentry.io/answers/write-one-or-more-lines-to-a-file-in-python/)*