Given an array of strings `strs`, group the **anagrams** together. You can return the answer in any order.
**Example 1:**
```
Input: strs = ["eat","tea","tan","ate","nat","bat"]
Output: [["bat"],["nat","tan"],["ate","eat","tea"]]
```
**Example 2:**
```
Input: strs = [""]
Output: [[""]]
```