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Python Flask Basics Welcome to Flask Clean URL Arguments

Posted by Zheng Liu
Zheng Liu
Courses Plus Student 308 Points

Add routes to implement "int + int", "int + float", "float + int" and "float + float". Simple method?

I need some help in trying to write routes to implement additions where each argument can be either int or float. One obvious way is to write 4 different routes to handle different types.

For example, the following codes

@app.route('/add/<int:num1>/<int:num2>') def addints(num1,num2): return "{} + {} = {}".format(num1,num2,num1+num2)

@app.route('/add/<float:num1>/<float:num2>') def addfloats(num1,num2): return "{} + {} = {}".format(num1,num2,num1+num2)

@app.route('/add/<int:num1>/<float:num2>') def addintfloat(num1,num2): return "{} + {} = {}".format(num1,num2,num1+num2)

can handle "int+int", "float+float" and "int+float". However, if I enter endpoint: /add/6.5/4, I got 404... Of course I can add yet another route to handle it, but I've pretty fed up with this hard-coding style. Is there a better way to manage all 4 possibilities by setting up the url?

Thanks very much!

1 Answer

John Lack-Wilson
John Lack-Wilson
8,181 Points
John Lack-Wilson
John Lack-Wilson
8,181 Points

You're absolutely right, we want to use the DRY principle.

You can specify one singular route i.e. @app.route('/add/<num1>/<num2>') - notice I'm not specifying parameter types here.

Then we can check if the parameters are floats or not - see here

If they are floats then we can use the float(variable) function to convert it to a float. If they are not floats we can use the int(variable) function.

Then you can do your addition. Also, don't worry about adding floats and integers together - if Python sees a float adding with an int, it will return a float.

Note you should also do some basic error handling for if the parameters are neither an int or a float to avoid odd results.

Zheng Liu
Zheng Liu
Courses Plus Student 308 Points

Wonderful! Thanks very much! Right, I agree that using the power of python may be the best solution.