Why does aiohttp.ClientSession() object .get() Method Return Results In Order Even Though It Is Asynchronous?

I found myself wondering if aiohttp.ClientSession() would return results sequentially because it was supposed to call a server many times, and then wait for all of the replies to arrive. I was expecting the results to be returned in a non-sequential order.

Additionally, the rate of replies varied, but strangely enough, they still remained in sequence.

I ran the below code multiple times:

async def main():
    async with aiohttp.ClientSession() as session:
        res_dict={}
        for number in range(1, 100):
            pokemon_url = f'https://pokeapi.co/api/v2/pokemon/{number}'
            async with session.get(pokemon_url) as resp:
                pokemon = await resp.json()
                res_dict[number]=pokemon['id']
                print(pokemon['id'])
        for i in res_dict:
            print(i, '=',res_dict[i])

asyncio.run(main())

And every time I ran it, I received the results in a perfectly ordered reply:

1
2
3
.
.
.
98
99

And they were also correctly paired up with each of their dict Keys as well:

1=1
2=2
3=3
.
.
.
98=98
99=99

Would I be correct to assume that like asyncio.gather(), an aiohttp.ClientSession object's .get() method will make queries and receive them asynchronously, only listing them if they arrive in order? I also noticed that the rate of replies being received varied, and that could be a possible explanation as to why this is happening.

Your assumption is correct. With quite a bit of modification, you can get async requests in a gather by creating a set of tasks like this:

import aiohttp
import asyncio


async def main():

    res_dict = {}

    # list of urls
    urls = []
    for number in range(1,20):
        pokemon_url = f'https://pokeapi.co/api/v2/pokemon/{number}'
        urls.append(pokemon_url)

    # list of tasks (with the gather)
    tasks = [asyncio.create_task(get_pokies(url)) for url in urls]
    responses = await asyncio.gather(*tasks)

    # make the dict
    for i, response in enumerate(responses):
        res_dict[i] = response['id']
        
    print(res_dict)


async def get_pokies(url):
    ''' async func for the reqest '''
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            return await response.json()


asyncio.run(main())

This will be much faster than the original code in the question, since now the requests are made "in parallel" as opposed to "in series"...