Question

如果在相应的输入框中没有输入任何内容，我该如何修改此程序，使其不包含“路点”的任何信息？换句话说，“数据”具有树部分，但如果没有输入任何内容，例如E2，我希望数据为[ { 'Way point1':(2,E1.get()), 'c':3.0 } ]

from Tkinter import *
import json

top = Tk()
L1 = Label(top, text="Way point1")
L1.pack()
E1 = Entry()

E1.pack()
L2 = Label(top, text="Way point2")
L2.pack()
E2 = Entry()
E2.pack()

def printout():
    data = [ { 'Way point1':(2,E1.get()), 'Way point2':(2, E2.get()), 'c':3.0 } ]
    print json.dumps(data, sort_keys=True, indent=2)

plus = Button(top,  text='+', command=printout).pack(side=LEFT)


top.mainloop()

Answer 1

仅使用2个航点，只需使用if语句：

waypoints = {'c': 3.0}
if E1.get():
    waypoints['Way point1']: (2, E1.get())
if E2.get():
    waypoints['Way point2']: (2, E2.get())

data = [waypoints]

Answer 2

如果您计划将来添加额外的航点，您可以将其构建到一个列表中进行迭代：

from Tkinter import *
import json

E = []
L = []
top = Tk()

number_of_waypoints = 2    

for n in range(1, number_of_waypoints+1): #+1 as 1...N
    l = Label(top, text="Way point%d" % n)
    l.pack()

    e = Entry()
    e.pack()

    E.append(e)
    L.append(l)


def printout():
    # Iterate over the zip of E & L (joined), building the dict using .cget('text') to get
    # the value of the Tkinter label. Add the { 'c':3.0 } to the end of the resulting list
    data = [ { l.cget("text"): (2,e.get()) } for e,l in zip(E,L) ] + [{ 'c':3.0 }]
    print json.dumps(data, sort_keys=True, indent=2)

plus = Button(top,  text='+', command=printout).pack(side=LEFT)

top.mainloop()

从JSON中省略空路点条目

2 个答案: