import flask from flask code example

Example 1: import flask

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, World!'

Example 2: export flask app

> set FLASK_APP=hello
> flask run

Example 3: default flask app

from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
    return 'Flask'

Example 4: how to import flask

from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"