# Extract SAS Dataset metadata using Python

SAS Datasets not only contain data but also a whole lot of metadata information within. The most commonly used information from this metadata is as follows - 
- Variable Name
- Variable Label
- Variable Type (num/char)
- Format
- Variable Position
- Length

In SAS, typically the PROC CONTENTS procedure is used by programmers to extract out this dataset level and column/variable level metadata; and it look something like this -

```
proc contents data = mycas.cars;
run;
```

![image.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1637338642267/6b6ERm5A8.png)

If you are trying to read this information using Python, then you have a couple of options, but here we will focus on an amazing Python library called `pyreadstat`. Some quick brief about `pyreadstat`

> 
About **pyreadstat**
>
Python package to read sas, spss and stata files into pandas data frames. It is a wrapper for the C library readstat.

Let's follow a few steps to understand how `pyreadstat` can be used to read SAS dataset metadata in a way that the output looks similar to the SAS Proc Contents output.

### Step 1.

Install `pyreadstat` on your computer, if you haven't already.

```
pip install  pyreadstat  pandas
```

### Step 2.

Start a new program `metadata.py` and import this library into the program.

```
import pyreadstat as prs
import pandas as pd
```

### Step 3.

Invoke the `.read_sas7bdat()` function from the `prs` object which reads the SAS dataset (data as well as metadata)

```
ae001, ae001_meta = prs.read_sas7bdat("c:/ae001.sas7bdat")
```

### Step 4.

Initialise an empty pandas dataframe and assign each piece of information as below.

```
# initalise empty pandas dataframe
df_metadata = pd.DataFrame()

# read column name, labels into the new pandas dataframe
df_metadata["name"] = meta.column_names
df_metadata["label"] = meta.column_labels
```

### Step 5.

Follow the same steps as above to read the remaining information - 
- format << meta.original_variable_types
- type << meta.readstat_variable_types
- length << meta.variable_storage_width


This [website](https://ofajardo.github.io/pyreadstat_documentation/_build/html/index.html) gives very good detail about the functions and parameters available in `pyreadstat` to read SAS datasets.

Hope you found this article useful. Happy coding!