python : No module named 'flask'

Question

所以我已经在这个问题上停留了一段时间了。对于我拥有的一个文件，它可以正常工作，并且允许我使用 flask 框架。使用此代码。

from flask import Flask, render_template
from flask import request
from flask import *
from datetime import datetime
from functools import wraps
import time
import csv
app = Flask(__name__)
app.secret_key ='lukey'
#displays index page
@app.route('/')
def home():
    return render_template('index.html')
#displays welcome page  
@app.route('/welcome')
def welcome():
    return render_template('welcome.html')
#allows user to login
@app.route('/log', methods=['GET','POST'])
def log():
    error = None
    if request.method == "POST":
        if request.form['user'] != 'admin' or  request.form['pass'] != 'admin':
            error = "Invalid credentials"
        else: 
            session['logged_in'] = True
            return redirect (url_for('welcome'))
    return render_template('log.html', error=error)
#allows user to logout
@app.route('/logout')
def logout():
    session.pop('logged_in', None)
    flash('you were logged out')
    return redirect (url_for('log'))
#function to check if admin is logged in
def login_required(test):
    @wraps(test)
    def wrap(*args, **kwargs):
        if 'logged_in' in session:
            return test(*args, **kwargs)
        else:
            flash('you need to login before using admin tools')
            return redirect(url_for('log'))
    return wrap
#Displays map
@app.route('/map')      
def map():
    return render_template('map.html')  
#Displays gallery
@app.route('/gallery')  
def gallery():
    return render_template('gallery.html')

#Allows users to view previous bookings 
@app.route('/bookings', methods = ['GET'])
def bookings():
    bookingsFile ='static\\bookings.csv'
    data = readFile(bookingsFile)
    return render_template('bookings.html', data=data)

#Allows user to request for a booking
@app.route('/addBookings', methods = ['POST'])  
def addBookings():
    bookingsFile = 'static\\bookings.csv'
    data = readFile(bookingsFile)
    bookingName = request.form[('name')]
    bookingEmail = request.form[('email')]
    bookingDate= request.form[('date')]
    #Converts the date string to unix timestamp
    bookingDateUnix = time.mktime(datetime.strptime(request.form[('date')], "%Y-%m-%d").timetuple())
    numberOfDays = request.form[('days')]
    #calculates the end date in unix form
    endDateUnix = int(numberOfDays)*24*60*60+int(bookingDateUnix)
    #converts the unix form end date to string
    newDate = datetime.fromtimestamp(int(endDateUnix)).strftime('%Y-%m-%d')
    #Calculates the price of the users stay
    price = int(numberOfDays) * 200
    #Will be changed by admin to confirm bookings
    hasBeenBooked = 'Awaiting confirmation'
    bookingsFile ='static\\bookings.csv'

    for row in data:
        prevBookingDateUnix = row[7]
        prevEndDateUnix = row[8]
        #Testing no double bookings
        if row[2] == bookingDate or row[6] == newDate:
            flash('This time has already been allocated')
            return redirect(url_for('bookings'))
        #Testing there are no crossover points
        elif float(prevBookingDateUnix) < bookingDateUnix and float(prevEndDateUnix) < bookingDateUnix and bookingDateUnix < endDateUnix:
            flash('valid input')    
        else: 
            flash('invalid input')
            return redirect(url_for('bookings'))
    #parameters parsed from input       
    newEntry =[bookingName, bookingEmail, bookingDate, numberOfDays, hasBeenBooked, price, newDate, bookingDateUnix, endDateUnix]
    data.append(newEntry)
    writeFile(data, bookingsFile)
    return render_template('bookings.html', data=data)
#allows viewing of comments in csv file
@app.route('/comments', methods = ['GET'])
def comments():
    commentsFile = 'static\\comments.csv'
    data = readFile(commentsFile)
    return render_template('comments.html', data=data)
#adding comments to csv file
@app.route('/addComments', methods = ['POST'])
def addComments():
# add an entry to the data
    #read the data from file
    commentsFile = 'static\\comments.csv'
    data = readFile(commentsFile)
    #add the new entry
    commentorsName = request.form[('commentorsName')]
    comment = request.form[('comment')]
    commentDate = datetime.now().strftime("%Y-%m-%d / %H:%M")
    newEntry = [commentorsName, comment, commentDate]
    data.append(newEntry)
    #save the data to the file
    writeFile(data, commentsFile)
    return render_template('comments.html', data=data)


#Ensures the administrator is logged in before comments are deleted
@app.route('/deleteComments', methods = ['POST'])   
@login_required
def deleteComments():
    f = open('static\\comments.csv', 'w')
    f.truncate()
    f.close()
    return render_template('comments.html')

#Ensures the administrator is logged in before bookings are deleted
@app.route('/deleteBookings', methods = ['POST'])   
@login_required
def deleteBookings():
    f = open('static\\bookings.csv', 'w')
    f.truncate()
    f.close()
    return render_template('bookings.html')

def readFile(aFile):
#read in 'aFile'
    with open(aFile, 'r') as inFile:
        reader = csv.reader(inFile)
        data = [row for row in reader]
    return data
def writeFile(aList, aFile):
#write 'aList' to 'aFile'
    with open(aFile, 'w', newline='') as outFile:
        writer = csv.writer(outFile)
        writer.writerows(aList)
    return
if __name__ == '__main__':
    app.run(debug = True)

但是使用这段代码会抛出错误。没有名为“ flask ”的模块

#!/usr/bin/python3.4
#
# Small script to show PostgreSQL and Pyscopg together
#

from flask import Flask, render_template
from flask import request
from flask import *
from datetime import datetime
from functools import wraps
import time
import csv
import psycopg2
app = Flask(__name__)
app.secret_key ='lukey'
def getConn():
    connStr=("dbname='test' user='lukey' password='lukey'")
    conn=psycopg2.connect(connStr)
    return conn

@app.route('/')
def home():
    return render_template(index.html)

@app.route('/displayStudent', methods =['GET'])
def displayStudent():
    residence = request.args['residence']
    try:
        conn = None
        conn = getConn()
        cur = conn.cursor()
        cur.execute('SET search_path to public')

        cur.execute('SELECT stu_id,student.name,course.name,home_town FROM student,\
                    course WHERE course = course_id AND student.residence = %s',[residence])
        rows = cur.fetchall()
        if rows:
            return render_template('stu.html', rows = rows, residence = residence)
        else:
            return render_template('index.html', msg1='no data found')

    except Exception as e:
        return render_template('index.html', msg1='No data found', error1 = e)

    finally:
        if conn:
            conn.close()

#@app.route('/addStudent, methods =['GET','POST']')
#def addStudent():

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

我觉得问题可能与我使用的 python/flask/pip 版本有关。任何想法谢谢。

Answer 1

您的 Python 版本是 2.X。

看看this question及其答案。

你最好的选择是使用 virtualenv，因为它使得处理包版本变得非常简单。 accepted answer如果您想为此应用程序使用 Python 3，则包含正确的命令提示符命令:

virtualenv -p C:\Python34\python.exe py3env
py3env\Scripts\activate
pip install package-name