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(io_csv)=

# CSV

Reading a csv is very straightforward with {py:func}`~datafusion.context.SessionContext.read_csv`

```python
from datafusion import SessionContext

ctx = SessionContext()
df = ctx.read_csv("file.csv")
```

An alternative is to use {py:func}`~datafusion.context.SessionContext.register_csv`

```python
ctx.register_csv("file", "file.csv")
df = ctx.table("file")
```

If you require additional control over how to read the CSV file, you can use
{py:class}`~datafusion.options.CsvReadOptions` to set a variety of options.

```python
from datafusion import CsvReadOptions
options = (
    CsvReadOptions()
    .with_has_header(True) # File contains a header row
    .with_delimiter(";") # Use ; as the delimiter instead of ,
    .with_comment("#")  # Skip lines starting with #
    .with_escape("\\")  # Escape character
    .with_null_regex(r"^(null|NULL|N/A)$")  # Treat these as NULL
    .with_truncated_rows(True) # Allow rows to have incomplete columns
    .with_file_compression_type("gzip")  # Read gzipped CSV
    .with_file_extension(".gz") # File extension other than .csv
)
df = ctx.read_csv("data.csv.gz", options=options)
```

Details for all CSV reading options can be found on the
[DataFusion documentation site](https://datafusion.apache.org/library-user-guide/custom-table-providers.html).