How to update text Labels in tkinter?

Question

Every time I click the button to get the weather (I used Json to get info from a website), the previous text remains and new text is printed under it, but I want the old text to be updated. How can I do that? Please help.

from tkinter import *
import requests
import json

root = Tk()
root.title("Weather")
root.geometry("600x400")

def RealWeather():

    try:
        api_request = requests.get("http://api.openweathermap.org/data/2.5/weather?appid=c2fc19de6fcd6869c4a9e167ee0f2eb7&q=" + city.get())
        api = json.loads(api_request.content)
        location = api['name'] + ", " + api['sys']['country']
        temp = int(api['main']['temp'] - 273.15)
        ws = api['wind']['speed']
        status = api['weather'][0]['main']

        Labelloc = Label(root, text="Location",background='#5182cf').grid(row=2,column=0)
        Label_loc = Label(root, text=location ,background='#5182cf').grid(row=2, column=1)

        Labeltemp = Label(root, text="Temperature",background='#5182cf').grid(row=3,column=0)
        Label_temp = Label(root, text=temp,background='#5182cf').grid(row=3,column=1)

        Labelws = Label(root, text="Wind Speed",background='#5182cf').grid(row=4,column=0)
        Label_ws = Label(root, text=ws,background='#5182cf').grid(row=4,column=1)

        Labelstatus = Label(root, text="Status",background='#5182cf').grid(row=5,column=0)
        Label_status = Label(root, text=status,background='#5182cf').grid(row=5,column=1)


    except Exception as e:
        api = "Error..."

    EmptyLabel = Label(root, text="", background='#5182cf').grid(row=1, column=0)


butn = Button(root, text="Search", command=RealWeather).grid(row=0, column=3)
Label1 = Label(root, text="Enter City: ").grid(row=0,column=0)
city = Entry(root)
city.grid(row=0, column=1, padx=20)

root.mainloop()

Answer 1

Here's how to fix your problems by using the universal widget config() method I mentioned in my comment:

from tkinter import *
import requests
import json

root = Tk()
root.title("Weather")
root.geometry("600x400")


def create_labels():
    global Label_loc, Label_temp, Label_ws, Label_status

    Label(root, text="Location",background='#5182cf').grid(row=2,column=0)
    Label_loc = Label(root, background='#5182cf')
    Label_loc.grid(row=2, column=1)

    Label(root, text="Temperature",background='#5182cf').grid(row=3,column=0)
    Label_temp = Label(root, background='#5182cf')
    Label_temp.grid(row=3,column=1)

    Labelws = Label(root, text="Wind Speed", background='#5182cf').grid(row=4,column=0)
    Label_ws = Label(root, background='#5182cf')
    Label_ws.grid(row=4,column=1)

    Labelstatus = Label(root, text="Status", background='#5182cf').grid(row=5,column=0)
    Label_status = Label(root, background='#5182cf')
    Label_status.grid(row=5,column=1)


def RealWeather():
    # Not strickly necessary, but good documentation.
    global Label_loc, Label_temp, Label_ws, Label_status

    try:
        api_request = requests.get("http://api.openweathermap.org/data/2.5/weather?appid=c2fc19de6fcd6869c4a9e167ee0f2eb7&q=" + city.get())
        api = json.loads(api_request.content)
        location = api['name'] + ", " + api['sys']['country']
        temp = int(api['main']['temp'] - 273.15)
        ws = api['wind']['speed']
        status = api['weather'][0]['main']

        Label_loc.config(text=location)
        Label_temp.config(text=temp)
        Label_ws.config(text=ws)
        Label_status.config(text=status)

    except Exception as e:
        print('error occurred:', e)


create_labels()
butn = Button(root, text="Search", command=RealWeather)
butn.grid(row=0, column=3)
Label1 = Label(root, text="Enter City: ")
Label1.grid(row=0,column=0)
city = Entry(root)
city.grid(row=0, column=1, padx=20)

root.mainloop()

P.S. I also strongly suggest you read and start following the PEP 8 - Style Guide for Python Code.

Answer 2

This is how I would proceed with your answer. First create the labels outside the function and use grid() on separate lines, so they are not None.

Labelloc = Label(root, text="Location",background='#5182cf')
Label_loc = Label(root)

Labeltemp = Label(root, text="Temperature",background='#5182cf')
Label_temp = Label(root)

Labelws = Label(root, text="Wind Speed",background='#5182cf')
Label_ws = Label(root)

Labelstatus = Label(root, text="Status",background='#5182cf')
Label_status = Label(root)

Now inside the function, you have to call the config() method to update the label each time the function is run:

Labelloc.grid(row=2,column=0) #grid it when the func is ran
Label_loc.config(text=location,background='#5182cf')
Label_loc.grid(row=2, column=1) #grid it when the func is ran

Labeltemp.grid(row=3,column=0) #grid it when the func is ran
Label_temp.config(background='#5182cf')
Label_temp.grid(row=3,column=1) #grid it when the func is ran

Labelws.grid(row=4,column=0) #grid it when the func is ran
Label_ws.config(text=ws,background='#5182cf')
Label_ws.grid(row=4,column=1) #grid it when the func is ran

Labelstatus.grid(row=5,column=0)
Label_status.config(text=status,background='#5182cf')
Label_status.grid(row=5,column=1)

So final code:

from tkinter import *
import requests
import json

root = Tk()
root.title("Weather")
root.geometry("600x400")

def RealWeather():

    try:
        api_request = requests.get("http://api.openweathermap.org/data/2.5/weather?appid=c2fc19de6fcd6869c4a9e167ee0f2eb7&q=" + city.get())
        api = json.loads(api_request.content)
        location = api['name'] + ", " + api['sys']['country']
        temp = int(api['main']['temp'] - 273.15)
        ws = api['wind']['speed']
        status = api['weather'][0]['main']

        Labelloc.grid(row=2,column=0)
        Label_loc.config(text=location,background='#5182cf')
        Label_loc.grid(row=2, column=1)

        Labeltemp.grid(row=3,column=0)
        Label_temp.config(background='#5182cf')
        Label_temp.grid(row=3,column=1)

        Labelws.grid(row=4,column=0)
        Label_ws.config(text=ws,background='#5182cf')
        Label_ws.grid(row=4,column=1)

        Labelstatus.grid(row=5,column=0)
        Label_status.config(text=status,background='#5182cf')
        Label_status.grid(row=5,column=1)

    except Exception as e:
        api = "Error..."

    EmptyLabel = Label(root, text="", background='#5182cf').grid(row=1, column=0)

butn = Button(root, text="Search", command=RealWeather).grid(row=0, column=3)
Label1 = Label(root, text="Enter City: ").grid(row=0,column=0)
city = Entry(root)
city.grid(row=0, column=1, padx=20)

Labelloc = Label(root, text="Location",background='#5182cf')
Label_loc = Label(root)

Labeltemp = Label(root, text="Temperature",background='#5182cf')
Label_temp = Label(root)

Labelws = Label(root, text="Wind Speed",background='#5182cf')
Label_ws = Label(root)

Labelstatus = Label(root, text="Status",background='#5182cf')
Label_status = Label(root)

root.mainloop()

If you wish to use threading then it would be like:

# all imports
import threading

.... #same all code 
butn = Button(root, text="Search", command=lambda: threading.Thread(target=RealWeather).start())
btn.grid(row=0, column=3)
.... #same all code

Why use threading? It wont freeze the GUI while python fetches data from api. Though using threading with tkinter is not a very good option, there are some downsides to it, but for this simple example, it might be fine to work with it.