flask pass variable from one function to another function

Question

As you can see the code. I want to pass variable q from function home() into function search().

@app.route("/",methods=['GET','POST'])
def home():
    result = Mylist.query.all()
    return render_template('index.html',result=result)
    q = request.form.get("q")

@app.route("/search.html")
def search():
        d = q
        var='%'+d+'%'
        result = Mylist.query.filter(Mylist.type.like(var)
        return render_template('search.html',result=result)

https://stackoverflow.com/a/27611281 this might help you, I found it better than existing answers. — Ritwik, Aug 19 '19 at 11:37

score 4 · Accepted Answer · edited May 16 '19 at 15:26

Where an index.html will contain:

<form action="/search.html" method="get" autocomplete="off" class="subscribe-form">
     <div class="form-group d-flex">
         <input type="text" class="form-control" placeholder="Enter your search" name="q" id="q" value="{{q}}">
         <input type="submit" value="Search" class="submit px-3">
     </div>
 </form>

Now you will see /search.html?q=top in url now you can easily pass this q=top by using q=request.args.get("q")...

@app.route("/search.html",methods=['GET'])
def search():
        q =request.args.get("q")
        d=str(q)
        var='%'+d+'%'
        myresult = Mylist.query.filter(Mylist.type.like(var)| Mylist.title.like(var)).all()

I am saving a filename in function and I need to pass that variable/filename to another function. Your solution is not possible in such casses. — JOSEPH Blessingh, Mar 20 '20 at 07:03

VC.One · Answer 2 · 2019-05-11T16:34:56.560

Option 1:

A variable created and updated inside a function exists only for that function.

From the Python documentation...

"If a variable is assigned a value anywhere within the function’s body, it’s assumed to be a local unless explicitly declared as global."

Solution:
Create q as a variable outside of functions, this way it's not just trapped inside function home but instead is now universally available to any and all functions. Any function can use or update such a variable.

Option 2:

Alternatively, you could just try passing q as a function parameter.

In example below, you will call function search but with parameter q added. The search function itself will reference that same q as a thing called input (or choose your own name/word).

@app.route("/",methods=['GET','POST'])
def home():
    result = Mylist.query.all()
    q = request.form.get("q")
    search( q )
    return render_template('index.html',result=result)


@app.route("/search.html")
def search( input ):
    d = input
    var='%'+d+'%'
    result = Mylist.query.filter(Mylist.type.like(var)
    return render_template('search.html',result=result)

It is showing an error, TypeError: search() missing 1 required positional argument: 'input' — nupur, May 12 '19 at 05:37
About _"search() missing 1 required parameter"_ sounds like you tried to call `search()` without giving it something to search for. As you can see, the function `def search( input ):` expects at least 1 thing to be provided as `input`... — VC.One, May 12 '19 at 17:40

score 1 · Answer 3 · answered Apr 09 '21 at 06:04

Define a global list append the variable from first view function to the list and access the last index value in the second view function.

var_list = []
@app.route("/",methods=['GET','POST'])
def home():
    result = Mylist.query.all()
    return render_template('index.html',result=result)
    q = request.form.get("q")
    var_list.append(q)

@app.route("/search.html")
def search():
        d = var_list.pop()
        var='%'+d+'%'
        result = Mylist.query.filter(Mylist.type.like(var)
        return render_template('search.html',result=result)

score -1 · Answer 4 · answered May 13 '19 at 11:42

your index.html will contain

<form action="/search.html" method="get" autocomplete="off" class="subscribe-form">
     <div class="form-group d-flex">
         <input type="text" class="form-control" placeholder="Enter your search" name="q" id="q" value="{{q}}">
         <input type="submit" value="Search" class="submit px-3">
     </div>
 </form>

==================================================================================

Now you will see /search.html?q=top in url now you can easily pass this q=top by using

q=request.args.get("q")

flask pass variable from one function to another function

4 Answers4

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