python async function code example

Example 1: python async await

import asyncio

async def print_B(): #Simple async def
    print("B")

async def main_def():
    print("A")
    await asyncio.gather(print_B())
    print("C")
asyncio.run(main_def())

# The function you wait for must include async
# The function you use await must include async
# The function you use await must run by asyncio.run(THE_FUNC())

Example 2: python async await

import asyncio
from PIL import Image
import urllib.request as urllib2

async def getPic(): #Proof of async def
    pic = Image.open(urllib2.urlopen("https://c.files.bbci.co.uk/E9DF/production/_96317895_gettyimages-164067218.jpg"))
    return pic

async def main_def():
    print("A")
    print("Must await before get pic0...")
    pic0 = await asyncio.gather(getPic())
    print(pic0)
asyncio.run(main_def())

Example 3: async sleep python

await asyncio.sleep(1)

Example 4: python async await

import signal
import sys
import asyncio
import aiohttp
import json

loop = asyncio.get_event_loop()
client = aiohttp.ClientSession(loop=loop)

async def get_json(client, url):
    async with client.get(url) as response:
        assert response.status == 200
        return await response.read()

async def get_reddit_top(subreddit, client):
    data1 = await get_json(client, 'https://www.reddit.com/r/' + subreddit + '/top.json?sort=top&t=day&limit=5')

    j = json.loads(data1.decode('utf-8'))
    for i in j['data']['children']:
        score = i['data']['score']
        title = i['data']['title']
        link = i['data']['url']
        print(str(score) + ': ' + title + ' (' + link + ')')

    print('DONE:', subreddit + '\n')

def signal_handler(signal, frame):
    loop.stop()
    client.close()
    sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)

asyncio.ensure_future(get_reddit_top('python', client))
asyncio.ensure_future(get_reddit_top('programming', client))
asyncio.ensure_future(get_reddit_top('compsci', client))
loop.run_forever()