学习python的第四天

def hanshu():
    a= ‘ 1 2 3 ‘
    b=a.replace(‘ ‘,‘‘)#替换
    print(b)
hanshu()

a = [1,1,2,2,3]
b = []
for i in a:
    if i not in b:
        b.append(i)#运行出来的放在b数组中
print(b)

a = [1,1,2,2,3]
a.remove(1)#移除数组里的第一个1
print(a)

import time
a = int(input("请输入一个数"))
for i in range(1,a):
    time.sleep(1)#程序休眠1秒
    print(‘%s %d%%\r‘%(‘#‘*i,i),end="",flush=True)

a = [1,2,3,4,5]
print(sorted(a,reverse=True))#reverse=True 翻转排序
#print(sorted(a[::-1])#[::-1]翻转这个跟这个题没关系

list1 = [[‘张卓‘,100],[‘妮姐‘,5],[‘AJ‘,10],[‘王鑫‘,200]]
print(sorted(list1,key=lambda x:x[1]))#规定以数字排序

f = [x for x in range(100)if x %==0]#简写循环
print(f)

diet_ = {1:100,‘a‘:‘b‘}
print(diet_.get(‘a‘))#动态字典用这个.get即使取不出来也不会报错

path = ‘\\Users\\Administrator\\Desktop\\Classes_.txt‘#注意这里的的‘\\Users\\Administrator\\Desktop\\Classes_.txt’是文件地址
open_ = open(path,mode=‘r‘,encoding=‘utf-8‘)
lines = open_.readlines()
dict_ = {}
for str_ in lines:
    str_1 = str_.strip(‘\n‘)
    key,value = str_1.split(‘ ‘)
    dict_[key] = value
num = input(‘>>‘)
value = dict_[num]
print(value)