Python Retaining variables from a text box.

[Ramone]

My issue is this. I can retrieve the chosenclass variable from the html text box, and the classroom of students is displayed, but after the updatepa function is called, that is after a student record has been updated, the variable is reset to the initial value of " " and so no class is displayed in the form.

I need a way of retaining the value of chosenclass. I'm thinking flask g or session might work but I'm not really sure how to implement this in my code. Or is there a better way of retaining a variable?

@app.route('/' , methods = ["GET", "POST"])
def Index():
        chosenclass = request.values.get('chosenclass')
        all_data = Data.query.filter_by(classroom=chosenclass).all()
        return render_template("index.html", students = all_data)

@app.route('/updatepa', methods = ['GET', 'POST'])

def updatepa():
    if request.method == 'POST':
        my_data = Data.query.get(request.form.get('id'))
        my_data.name = request.form['name']
        my_data.studentid = request.form['studentid']
        my_data.classroom = request.form['classroom']
        my_data.classtime = request.form['classtime']
        my_data.pacomment = request.form['pacomment']

        db.session.commit()
        flash("Student Updated Successfully")
        return redirect(url_for('Index'))

I have tried chosenclass = request.g.get('chosenclass') but receive the error message AttributeError: 'Request' object has no attribute 'g'

Any thoughts on how to go about this would be appreciated
Thanks
Ramone

 

[Malcolm]

Hi there,

I appreciate that you used the BBCode, but just a suggestion... When you are posting long bits if code its best to use the </>.

This is a little out of my league, however, I'll see who might be able to answer this!

@Krusty the Senile @swift @Ghost @simong1993

 

[Ramone]

Thanks Malcolm. I'll remember to enclose the code in </> in future. In the meantime, I'll keep chipping away at it and experiment with flask g or sessions in a smaller project. But I am still open to any ideas on the best way to approach this issue.

 

[Ghost]

x = "awesome"

def myfunc()
  global x
  x = "fantastic"
  print("Python is " + x)

myfunc()

print("Python is " + x)

This is the answer to your question from w3schools - an incredible resource for learning many programming languages.

Python Global Variables

W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.

www.w3schools.com

You need to declare a variable outside of the function scope first, as you can see above. The word 'global' is used to show that the variable being used inside the function is actually a reference to a variable not given to the function as a parameter.

For example, in almost any programming language you can search "how to use global variable in language?" or "language global variables" will almost always pull up a tutorial or example code for how to access a variable in a function, change it, etc.

 

[Ramone]

Thanks for that Ghost. I'll look in to that way of handling this..