爲什麼我得到這個NameError：name'url_for'沒有被定義？

我試圖打造繼燒瓶教程的指令的URL爲什麼我得到這個NameError：name'url_for'沒有被定義？

http://flask.pocoo.org/docs/0.11/quickstart/

但是我保持得到這個NameError

名 'url_for' 沒有定義

這是代碼：

from flask import Flask 

app = Flask(__name__) 

@app.route('/') 
def Index() : pass 

@app.route ('/ login') 
def loGin() : pass 

@app.route('/user/<username>') 
def profile(username) : pass 


with app.test_request_context() : 
    print url_for('Index') 
    print url_for('loGin') 
    print url_for('loGin', next='/') 
    print url_for('profile', username = 'Jon DD')

這是總的錯誤消息：

eloiim:minimalapp iivri.andre$ export FLASK_APP=Greet.py 
eloiim:minimalapp iivri.andre$ flask run 
Traceback (most recent call last): 
    File "/usr/local/bin/flask", line 11, in <module> 
    sys.exit(main()) 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 478, in main 
    cli.main(args=args, prog_name=name) 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 345, in main 
    return AppGroup.main(self, *args, **kwargs) 
    File "/usr/local/lib/python2.7/site-packages/click/core.py", line 696, in main 
    rv = self.invoke(ctx) 
    File "/usr/local/lib/python2.7/site-packages/click/core.py", line 1060, in invoke 
    return _process_result(sub_ctx.command.invoke(sub_ctx)) 
    File "/usr/local/lib/python2.7/site-packages/click/core.py", line 889, in invoke 
    return ctx.invoke(self.callback, **ctx.params) 
    File "/usr/local/lib/python2.7/site-packages/click/core.py", line 534, in invoke 
    return callback(*args, **kwargs) 
    File "/usr/local/lib/python2.7/site-packages/click/decorators.py", line 64, in new_func 
    return ctx.invoke(f, obj, *args[1:], **kwargs) 
    File "/usr/local/lib/python2.7/site-packages/click/core.py", line 534, in invoke 
    return callback(*args, **kwargs) 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 388, in run_command 
    app = DispatchingApp(info.load_app, use_eager_loading=eager_loading) 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 124, in __init__ 
    self._load_unlocked() 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 148, in _load_unlocked 
    self._app = rv = self.loader() 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 209, in load_app 
    rv = locate_app(self.app_import_path) 
    File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 89, in locate_app 
    __import__(module) 
    File "/Users/iivri.andre/Documents/minimalapp/Greet.py", line 16, in <module> 
    print url_for('Index') 
NameError: name 'url_for' is not defined

我不知道是什麼問題。幫助將非常感激。

乾杯 Andre。

來源

2016-11-29 siur

由於錯誤表示，由於'url_for'沒有定義。你需要導入它。 'from Flask import url_for' –

當Python說某些東西沒有定義，並且你認爲它是時，找出它的定義位置。你會發現它不是。 – kindall

將它添加到你的導入行：

from flask import Flask, url_for

來源

2016-11-29 19:45:00 abigperson

爲什麼我得到這個NameError：name'url_for'沒有被定義？

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