> For the complete documentation index, see [llms.txt](https://docs.trymito.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.trymito.io/how-to/combining-dataframes.md).

# Combining Dataframes

Join datasets together by selecting keys, concatenate dataframes on top of each other, or find unique values between datasets.

## Why combine dataframes

If you have mulitple dataframes, it can be useful to combine them into a single dataframe. This may be because they share a key, and you want to analyze the data together, or that the dataframes are each pieces of a larger dataset that were split up for performance reasons, or something else entirely. Mito has tools that make combining these dataframes together incredibly easy!

## Different ways to combine data:

{% hint style="info" %}
Looking to include use VLOOKUP like in Excel? In Mito, you can use the VLOOKUP formula just like Excel. See the formula documentation [here](/how-to/interacting-with-your-data/mito-spreadsheet-formulas.md#vlookup). 
{% endhint %}

Merge combines dataframes based on values in shared columns (like a VLOOKUP in Excel):

{% content-ref url="/pages/-MYIPtvCumDYNsdH5-vZ" %}
[Merge (horizontal)](/how-to/combining-dataframes/merging-datasets-together.md)
{% endcontent-ref %}

Concat is used to stack two dataframes on top of eachother:

{% content-ref url="/pages/UUUgKohLKTlWDonN3VrD" %}
[Concatenate (horizontal)](/how-to/combining-dataframes/concatenate-dataframes.md)
{% endcontent-ref %}

Dataframe difference calculates the difference between two dataframes:

{% content-ref url="/pages/Gojqxwy80WzankuE6716" %}
[Anti-merge (unique)](/how-to/combining-dataframes/anti-merge-unique.md)
{% endcontent-ref %}


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