我的python3学习笔记

windows下安装pip

安装好python之后，pip也就安装好了，但是需要把D:\Program Files\Python34\Scripts加到环境变量Path里，这样就能直接使用pip命令了,例如"pip install Pillow".

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判断字符串是否为数字:

import os
print("123".isdigit())
os.system("pause")

获得字符串长度:

import os
print(len("123"))
os.system("pause")

长字符串

import os
string = ("this is a "
          "really long long "
          "string")
print(string.isdigit())
os.system("pause")

去除首尾的空格和特殊符号

s.strip()
s.lstrip()
s.rstrip()
s.rstrip(',')

两个字符串的与操作

import os
s1="123456"
s2="123"
print(s1 and s2)
os.system("pause")

字符串转换大小写

import os
a="abcdEFG"
print(a.upper())
print(a.lower())
os.system("pause")

截取字符串,以及浮点数向上取整和向下取整

import os
import math
text="12345" 
s = 0 
e = math.ceil((len(text))/2)
print(e)
e = math.floor((len(text))/2)
print(e)
print(text[s:e] )
os.system("pause")

indexOf

import os
import math
text="hello world" 
pos=text.index("wor")
print(text[pos:] )
os.system("pause")

打印字符串中的所有字符

import os
import math
text="hello world" 
for c in text:
    print(c,end=" ")
os.system("pause")

翻转字符串

import os
import math
text="hello world" 
print(text[::-1])
os.system("pause")

以指定分割符拼接一个list中的所有项

import os
import math
seperator="."
mylist = ['jim', 'tom', 'bob', 'john']
print(seperator.join(mylist))
os.system("pause")

过滤字符串,只留下字母和数字

import os
def onlyLetterAndNumber(s):
    s2 = s.lower();
    fomart = 'abcdefghijklmnopqrstuvwxyz0123456789'
    for c in s2:
        if not c in fomart:
            s = s.replace(c,'');
    return s;
 
print(onlyLetterAndNumber("a000 aa-b"))
os.system("pause")

判断list是否为空,是否有元素

#coding: utf-8
import os
def isListEmpty(a):
    if not a:
        print("list is empty")
    else:
        print("list is not empty")


a=["a"]
isListEmpty(a)
del a[:]  #清空list
isListEmpty(a)
os.system("pause")

生成一个有序list,再打乱

#coding: utf-8
import random
import os
# works in place
l = list(range(4))
random.shuffle(l)
print(l)
os.system("pause")

在一个list后面追加list

#coding: utf-8
import os
x = [1, 2, 3]
x.append([4, 5])  #[1, 2, 3, [4, 5]]
print(x)
x = [1, 2, 3]
x.extend([4, 5])
print(x)  #[1, 2, 3, 4, 5]
os.system("pause")
''' 
多行注释
'''

在list中查找某个值

#coding: utf-8
import os
print(["foo","bar","baz"].index('bar'))
os.system("pause")

对list进行排序,条件是字母顺序

#coding: utf-8
import os
from operator import itemgetter
list_to_be_sorted=["foo","bar","baz"]
newlist = sorted(list_to_be_sorted, key=lambda k: k) 
print(newlist)
list_to_be_sorted=[{'name':'Homer', 'age':39}, {'name':'Bart', 'age':10}]
newlist = sorted(list_to_be_sorted, key=lambda k: k["name"]) 
print(newlist)

newlist = sorted(list_to_be_sorted, key=itemgetter('name')) 
print(newlist)
os.system("pause")

随机从list中选取一项

#coding: utf-8
import os
import random
foo = ['a', 'b', 'c', 'd', 'e']
print(random.choice(foo))
os.system("pause")

对一个int的list进行倍乘

#coding: utf-8
import os
new_list = [i * 2 for i in [1, 2, 3]]
print(new_list)
os.system("pause")

合并2个字典

#coding: utf-8
import os
x = {'a':1, 'b': 2}
y = {'b':10, 'c': 11}
z = x.copy()
z.update(y)
print(z)
os.system("pause")

GUI

tkinter.ttk

from tkinter import *

class Application(Frame):
    def say_hi(self):
        print ("hi there, everyone!")

    def createWidgets(self):
        self.QUIT = Button(self)
        self.QUIT["text"] = "QUIT"
        self.QUIT["fg"]   = "red"
        self.QUIT["command"] =  self.quit

        self.QUIT.pack({"side": "left"})

        self.hi_there = Button(self)
        self.hi_there["text"] = "Hello",
        self.hi_there["command"] = self.say_hi

        self.hi_there.pack({"side": "left"})

    def __init__(self, master=None):
        Frame.__init__(self, master)
        self.pack()
        self.createWidgets()

root = Tk()
app = Application(master=root)
app.mainloop()
root.destroy()

GUI 2

from tkinter import *
from tkinter import ttk

def calculate(*args):
    try:
        value = float(feet.get())
        meters.set((0.3048 * value * 10000.0 + 0.5)/10000.0)
    except ValueError:
        pass
    
root = Tk()
root.title("Feet to Meters")

mainframe = ttk.Frame(root, padding="3 3 12 12")
mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
mainframe.columnconfigure(0, weight=1)
mainframe.rowconfigure(0, weight=1)

feet = StringVar()
meters = StringVar()

feet_entry = ttk.Entry(mainframe, width=7, textvariable=feet)
feet_entry.grid(column=2, row=1, sticky=(W, E))

ttk.Label(mainframe, textvariable=meters).grid(column=2, row=2, sticky=(W, E))
ttk.Button(mainframe, text="Calculate", command=calculate).grid(column=3, row=3, sticky=W)

ttk.Label(mainframe, text="feet").grid(column=3, row=1, sticky=W)
ttk.Label(mainframe, text="is equivalent to").grid(column=1, row=2, sticky=E)
ttk.Label(mainframe, text="meters").grid(column=3, row=2, sticky=W)

for child in mainframe.winfo_children(): child.grid_configure(padx=5, pady=5)

feet_entry.focus()
root.bind('', calculate)

root.mainloop()
 

GUI 3

import tkinter as tk
from tkinter import ttk


LARGE_FONT= ("Verdana", 12)


class SeaofBTCapp(tk.Tk):

    def __init__(self, *args, **kwargs):
        
        tk.Tk.__init__(self, *args, **kwargs)

        #tk.Tk.iconbitmap(self,default='clienticon.ico')
        tk.Tk.wm_title(self, "Sea of BTC Client")

        container = tk.Frame(self)
        container.pack(side="top", fill="both", expand = True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)

        self.frames = {}

        for F in (StartPage, PageOne, PageTwo):

            frame = F(container, self)
            self.frames[F] = frame
            frame.grid(row=0, column=0, sticky="nsew")

        self.show_frame(StartPage)

    def show_frame(self, cont):

        frame = self.frames[cont]
        frame.tkraise()

        
class StartPage(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self,parent)
        
        label = ttk.Label(self, text="Start Page", font=LARGE_FONT)
        label.pack(pady=10,padx=10)

        button = ttk.Button(self, text="Visit Page 1",
                            command=lambda: controller.show_frame(PageOne))
        button.pack()

        button2 = ttk.Button(self, text="Visit Page 2",
                            command=lambda: controller.show_frame(PageTwo))
        button2.pack()


class PageOne(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        label = ttk.Label(self, text="Page One!!!", font=LARGE_FONT)
        label.pack(pady=10,padx=10)

        button1 = ttk.Button(self, text="Back to Home",
                            command=lambda: controller.show_frame(StartPage))
        button1.pack()

        button2 = ttk.Button(self, text="Page Two",
                            command=lambda: controller.show_frame(PageTwo))
        button2.pack()


class PageTwo(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        label = ttk.Label(self, text="Page Two!!!", font=LARGE_FONT)
        label.pack(pady=10,padx=10)

        button1 = ttk.Button(self, text="Back to Home",
                            command=lambda: controller.show_frame(StartPage))
        button1.pack()

        button2 = ttk.Button(self, text="Page One",
                            command=lambda: controller.show_frame(PageOne))
        button2.pack()
        


app = SeaofBTCapp()
app.mainloop()