python知识点复习

l1=[4,7,3,5,6,4,3,0]
print(l1)
l1.sort(reverse=True)
print(l1)
l1.reverse()
print(l1)
l1.insert(2, 78)
print(l1)
print(l1.index(78))

s="abcdebf"
print(s.find('b'))
print(s.rfind('b'))

l1=[1,2,3]
l2=[4,5,6]
print(l1+l2)

a1=(1,2,3)
a2=(3,4,5)
print(a1+a2)

def print_human(name, age = 23):
	print("body info: name is %s, age is %s" % (name, age) )
	
print_human("wangwu")
print_human("lisi", 25)
print_human("zhangsan", age = 36)

# *arge传入的是元组，**kwarges传入的是字典
def go(*arge,**kwarges):
    print(arge)
    print(kwarges)
l1=[1,2,3,3]
l2={'zhangsan':98,"lisi":56}
go(*l1,**l2)

#可利用元组返回多个值
def g1():
    a=6
    b=12
    c=15
    return a,b,c
a,b,c=g1() #序列解包
print(a,b,c)

文本操作

with open("suiji.txt","w+",encoding="utf-8") as fp:
    for i in range(100):
        a=random.randint(1, 100)
        fp.write(str(a)+'\n')

with open("../data/tongji.csv","r",encoding="utf-8") as fp:
    s=fp.read()
    print(s)
    print(len(s))
    a,b,c=0,0,0
    for i in s:
        if i.isupper():
            a+=1
        elif i.islower():
            b+=1
        elif i.isdigit():
            c+=1
    print(a,b,c)

#关键点在于用csv模块，可去除换行字符，只保留数据
#第二个关键点在与跳过第一行，用eval转换
import csv
with open("../data/pingjun.csv",'r+') as fp:
    s=csv.reader(fp)
    next(fp)
    num=0
    for row in s:
        num=num+sum([eval(x) for x in row])
    print(num)

with open('../data/test-row.txt','r+') as fp:
    s=fp.readlines()
    for row in s:
        if row.startswith('#')==0:
            print(row)

import os
path=os.getcwd() #获得当前路径
oldname=os.listdir('../data') #获得相对路径下的文件名
print(oldname) # 修改当前py文件所在位置
os.chdir('../data') #改变工作路径，方便下一步修改名字
for name in oldname:
   os.rename(name, name)