> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pandas-ai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Backwards Compatibility

> Using v2 classes in PandasAI v3

<Note>
  PandasAI v3 maintains backward compatibility for `SmartDataframe`,
  `SmartDatalake`, and `Agent`. However, we recommend migrating to the new
  `pai.DataFrame()` and `pai.chat()` methods for better performance and
  features.
</Note>

## SmartDataframe

`SmartDataframe` continues to work in v3 with the same API. However, you must configure the LLM globally.

### Using SmartDataframe in v3 (Legacy)

```python theme={null}
from pandasai import SmartDataframe
import pandasai as pai
import pandas as pd
from pandasai_litellm.litellm import LiteLLM

# Configure LLM globally (required)
llm = LiteLLM(model="gpt-4o-mini", api_key="your-api-key")
pai.config.set({"llm": llm})

# v2 style still works
df = pd.DataFrame({
    "country": ["US", "UK", "France"],
    "sales": [5000, 3200, 2900]
})

smart_df = SmartDataframe(df)
response = smart_df.chat("What are the top countries by sales?")
```

### Recommended v3 Approach

While `SmartDataframe` works, we recommend using `pai.DataFrame()` for better integration with v3 features:

```python theme={null}
import pandasai as pai
import pandas as pd

# Configure LLM globally
pai.config.set({"llm": llm})

# Simple approach
df = pd.DataFrame({
    "country": ["US", "UK", "France"],
    "sales": [5000, 3200, 2900]
})
df = pai.DataFrame(df)
response = df.chat("What are the top countries by sales?")
```

**Benefits of pai.DataFrame():**

* Better integration with semantic layer
* Improved context management
* Enhanced performance
* Access to v3-specific features
* Cleaner API

## SmartDatalake

`SmartDatalake` still works but is no longer necessary. You can query multiple dataframes directly with `pai.chat()`.

### Using SmartDatalake in v3 (Legacy)

```python theme={null}
from pandasai import SmartDatalake
import pandasai as pai
import pandas as pd
from pandasai_litellm.litellm import LiteLLM

# Configure LLM globally (required)
llm = LiteLLM(model="gpt-4o-mini", api_key="your-api-key")
pai.config.set({"llm": llm})

# v2 style still works
employees_df = pd.DataFrame({
    "name": ["John", "Jane", "Bob"],
    "department": ["Sales", "Engineering", "Sales"]
})

salaries_df = pd.DataFrame({
    "name": ["John", "Jane", "Bob"],
    "salary": [60000, 80000, 55000]
})

lake = SmartDatalake([
    employees_df,
    salaries_df
])

response = lake.chat("Who gets paid the most?")
```

### Recommended v3 Approach

Query multiple dataframes directly without `SmartDatalake`:

```python theme={null}
import pandasai as pai

# Configure LLM globally
pai.config.set({"llm": llm})

# Create dataframes
employees = pai.DataFrame(employees_df)
salaries = pai.DataFrame(salaries_df)

# Query across multiple dataframes directly
response = pai.chat("Who gets paid the most?", employees, salaries)
```

**Benefits of pai.chat():**

* No need to instantiate `SmartDatalake`
* Cleaner, more intuitive API
* Better performance
* Semantic layer support
* Easier to add/remove dataframes dynamically

## Agent

The `Agent` class works mostly the same way in v3 as it did in v2, but some methods have been removed. The main requirement is to configure the LLM globally.

```python theme={null}
from pandasai import Agent
import pandasai as pai
from pandasai_litellm.litellm import LiteLLM

# Configure LLM globally (required in v3)
llm = LiteLLM(model="gpt-4o-mini", api_key="your-api-key")
pai.config.set({"llm": llm})

# Agent works as before
df1 = pai.DataFrame(sales_data)
df2 = pai.DataFrame(costs_data)

agent = Agent([df1, df2])
response = agent.chat("Analyze the data and provide insights")
```

**Key Change:** Configure LLM globally with `pai.config.set()` instead of passing it per-agent.

### New Agent Methods in v3

PandasAI v3 introduces new Agent methods that enhance conversational capabilities:

* **`follow_up(query)`**: Continue conversations without clearing memory (maintains context)

```python theme={null}
agent = Agent([df1, df2])

# Start conversation
response = agent.chat('What is the total revenue?')

# Follow up without losing context
follow_up = agent.follow_up('What about last quarter?')
```

**Note:** The `clarification_questions()`, `explain()` and `rephrase_query()` methods have been removed in v3.

These methods provide enhanced conversational capabilities not available in v2.

For detailed information about Agent usage, see the [Agent documentation](/v3/agent). For information about using Skills with Agent, see the [Skills documentation](/v3/skills).