he-028

# HumanEval/28

Implement a file **`solution.py`** that completes the function below. Keep the given name and signature; your file must define it at module level.

```python
from typing import List


def concatenate(strings: List[str]) -> str:
    """ Concatenate list of strings into a single string
    >>> concatenate([])
    ''
    >>> concatenate(['a', 'b', 'c'])
    'abc'
    """
```

<!-- imported from OpenAI HumanEval (HumanEval/28) -->

# Auto-generated from OpenAI HumanEval HumanEval/28. Do not edit by hand.
from solution import *  # noqa: F401,F403 (prompt helpers may be referenced by tests)
from solution import concatenate as candidate

METADATA = {
    'author': 'jt',
    'dataset': 'test'
}


def check(candidate):
    assert candidate([]) == ''
    assert candidate(['x', 'y', 'z']) == 'xyz'
    assert candidate(['x', 'y', 'z', 'w', 'k']) == 'xyzwk'


def test_he_028():
    check(candidate)

You are an expert programmer. Solve the task exactly as specified. Output your solution as fenced code blocks using the required file name(s) and the exact function/type signatures requested. Prefer correctness; do not include prose outside code unless asked.

```python
from typing import List


def concatenate(strings: List[str]) -> str:
    """ Concatenate list of strings into a single string
    >>> concatenate([])
    ''
    >>> concatenate(['a', 'b', 'c'])
    'abc'
    """
    return ''.join(strings)
```

The user wants a Python function `concatenate` that takes a list of strings and returns a single concatenated string.
The function signature is:
```python
def concatenate(strings: List[str]) -> str:
```
The examples show:
`concatenate([])` -> `''`
`concatenate(['a', 'b', 'c'])` -> `'abc'`

This is a straightforward task. I can use `''.join(strings)`.

Let's write out the full solution.
I need to make sure the file is named `solution.py` and contains the function.

```python
from typing import List

def concatenate(strings: List[str]) -> str:
    return ''.join(strings)
```

Check constraints: "Keep the given name and signature; your file must define it at module level."
The prompt gives the docstring and type hints. I'll include them.

Everything looks correct.
I will output the code block.
No extra fluff.
Done. 
Let's double check.
`''.join([])` returns `''`.
`''.join(['a', 'b', 'c'])` returns `'abc'`.
Matches examples.
Ready. 
Output matches request.✅
Proceeds. 
Output generation. 
```python
from typing import List


def concatenate(strings: List[str]) -> str:
    """ Concatenate list of strings into a single string
    >>> concatenate([])
    ''
    >>> concatenate(['a', 'b', 'c'])
    'abc'
    """
    return ''.join(strings)
```
All good. 
I will produce exactly this. 
No extra text. 
Done. 
[Output Generation] -> *Proceeds*