单选框默认选中

# __author__ = " Caric Lee "
'''单选框'''
import tkinter as tk
import requests
root = tk.Tk()
root.title("xxx")
root.geometry('200x100')

# 提示框
var = tk.StringVar()   # 第一个字符串变量值
var.set('A')  # 默认选中 value='A'
l = tk.Label(root, bg='yellow', width=20, text='empty')  # textvariable 文本变量值
l.pack()


s = requests.session()
url = "https://crm.xiaoshouyi.com/global/do-login.action"
body = {
    "loginName": "88428977@qq.com",
    "password": "111111",
    "pcCodeForFocusMedia": 0
}
a = s.post(url, data=body, verify=False)
data = a.json()

# 单选按键框1
def print_selection():
    l.config(text='you have selectes' + var.get())  # 改变Label内的text
r1 = tk.Radiobutton(root, text='OptionA', variable=var, value='A',
                    command=print_selection)  # 选择了variable的var， 会被赋值成A，command触发动作
r1.pack()
# 单选按键框2
def print_selection():
    l.config(text='you have selectes' + var.get())  # 改变Label内的text
r2 = tk.Radiobutton(root, text='OptionB', variable=var, value='B',
                    command=print_selection)  # 选择了variable的var， 会被赋值成A，command触发动作
r2.pack()
# 单选按键框3
def print_selection():
    l.config(text='you have selectes' + var.get())  # 改变Label内的text
r3 = tk.Radiobutton(root, text='OptionC', variable=var, value='C',
                    command=print_selection)  # 选择了variable的var， 会被赋值成A，command触发动作
r3.pack()



root.mainloop()