Python学习笔记（三）

simple GUI with Tkinter

from tkinter import *

window=Tk()

label=Label(window,text="welcome to python")

button=Button(window,text="Click")

label.pack()

button.pack()

#pack():

window.mainloop()

#mainloop() detects and processes the events, if the close message releases, the window will close.

def processOK():

print("OK button is clicked.")

btOK=Button(window,text="OK",fg="red",bg="green",command=processOK)

btOK.pack()

window.mainloop()

---

label和message的区别：

TheMessagewidget is a variant of theLabel, designed to display multiline messages. The message widget can wrap text, and adjust its width to maintain a given aspect ratio.

message是label的一个变体，用于将文字多行显示，并且可以指定一行文字的宽度。而label是单行显示。

---

list

numbers = []

elements=5

for i in range(elements):

    value=eval(input("Enter a new number: "))

    numbers.append(value)

count=0

for i in range(elements):

    if numbers[i]>0:

        count+=1

list1 = list()

list2 = list([2, 3, 4])

list3 = list(["red", "green", "yellow"])

list4 = list(range(3, 6))

list5 = list("abcd")

list2[0:2] #list2[0] ~ list[1]

>>>list1 = [2, 3]

>>>list2 = 3 * list1

>>>list2

[2, 3, 2, 3, 2, 3]

>>>list1=[ x for x in range(5)]

>>>list1

[0, 1, 2, 3, 4] 

>>>list2=[0.5 * x for x in list1]

>>>list2

[0.0, 0.5, 1.0, 1.5, 2.0]

>>>list3=[x for x in list2 if x<1.5]

>>>list3

[0.0, 0.5, 1.0]

---

append(x)

remove(x)

count(x) #输出x在list中出现的次数

extend(list1) #把list1加到list后面

index(x)

insert(index, x) #把x插入index位置，index后面的元素后移一位

pop() #把最后一个元素弹出

reverse() #翻转list

sort() #升序排序list

---