尽管已安装，但没有名为flask 的模块

Question

New to flask and python here. I've written a simple python app, but when i run python app.py , I get ImportError: No module named flask .

app.py:

from flask import Flask

app = Flask(__name__)
def hello():
    return "Hello World!"

if __name__ == "__main__":
    app.run(debug=True)

Versions:

Flask 1.0.2
Python 2.7.10 (default, Oct  6 2017, 22:29:07)

EDIT:

Typing pip freeze gives me:

altgraph==0.10.2
bdist-mpkg==0.5.0
bonjour-py==0.3
click==6.7
Flask==1.0.2
itsdangerous==0.24
Jinja2==2.10
macholib==1.5.1
MarkupSafe==1.0
matplotlib==1.3.1
modulegraph==0.10.4
numpy==1.8.0rc1
py2app==0.7.3
pyobjc-core==2.5.1
pyobjc-framework-Accounts==2.5.1
pyobjc-framework-AddressBook==2.5.1
pyobjc-framework-AppleScriptKit==2.5.1
pyobjc-framework-AppleScriptObjC==2.5.1
pyobjc-framework-Automator==2.5.1
pyobjc-framework-CFNetwork==2.5.1
pyobjc-framework-Cocoa==2.5.1
pyobjc-framework-Collaboration==2.5.1
pyobjc-framework-CoreData==2.5.1
pyobjc-framework-CoreLocation==2.5.1
pyobjc-framework-CoreText==2.5.1
pyobjc-framework-DictionaryServices==2.5.1
pyobjc-framework-EventKit==2.5.1
pyobjc-framework-ExceptionHandling==2.5.1
pyobjc-framework-FSEvents==2.5.1
pyobjc-framework-InputMethodKit==2.5.1
pyobjc-framework-InstallerPlugins==2.5.1
pyobjc-framework-InstantMessage==2.5.1
pyobjc-framework-LatentSemanticMapping==2.5.1
pyobjc-framework-LaunchServices==2.5.1
pyobjc-framework-Message==2.5.1
pyobjc-framework-OpenDirectory==2.5.1
pyobjc-framework-PreferencePanes==2.5.1
pyobjc-framework-PubSub==2.5.1
pyobjc-framework-QTKit==2.5.1
pyobjc-framework-Quartz==2.5.1
pyobjc-framework-ScreenSaver==2.5.1
pyobjc-framework-ScriptingBridge==2.5.1
pyobjc-framework-SearchKit==2.5.1
pyobjc-framework-ServiceManagement==2.5.1
pyobjc-framework-Social==2.5.1
pyobjc-framework-SyncServices==2.5.1
pyobjc-framework-SystemConfiguration==2.5.1
pyobjc-framework-WebKit==2.5.1
pyOpenSSL==0.13.1
pyparsing==2.0.1
python-dateutil==1.5
pytz==2013.7
scipy==0.13.0b1
six==1.4.1
vboxapi==1.0
Werkzeug==0.14.1
xattr==0.6.4
zope.interface==4.1.1

Also, FWIW, if I run the app using python3 app.py, then it seems to work. Why does the command python though seem to point to python version 2 instead of version 3? I'm wondering if I messed up installation somewhere.

Any ideas greatly appreciated!

Answer 1

First of all verify the path of your python and pip using

which python
which pip

Verify if the base path is same. Also if you are using virtualenv or pipenv then make sure to activate the instance before executing the code.

Also try to do this

$ python
>>> import flask

check if the python version is the same that you are using. you can also follow this guide for flask Flask tutorial