python 基础（八）文件的读、写、改

'''
读、写文件
'''
# r：读；w：写；a：追加；r+：读写；w+：写读；a+:追加读写；
# rb：读二进制文件（包含视频、音频、网络传输）；wb：写二进制文件（默认为r）
f = open('test','r',encoding='utf-8')     #文件句柄
#read：读
data = f.read()
print(data)
#write:写，覆盖原有的文件内容
f.write('读数据，写入，，，，
')
f.write('测试，，，，')
#打印出文件内容并修改第5行展示
count = 0
for line in f:
    if count == 5:
        print('----------------')
        count +=1
        continue
    print(line)
    count +=1
#close:关闭
f.close()

#with：打开文件，不需要执行关闭命令，自动关闭；可同时打开多个文件
with open('test','r',encoding='utf-8') as c,
    open('test.bak','r',encoding='utf-8') as x:
    for lime in c:
        print(lime)

print(f.flush())    #flush：强制刷新（正常写入需要加入缓存，缓存到一定容量在写入到硬盘，该命令是实时更新到硬盘）
'''
进度条游戏，flush练习
'''
import  sys,time
for i in range(20):
    sys.stdout.write('#')
    sys.stdout.flush()
    time.sleep(0.1)

---

'''
修改文件
'''
z = open('test','r',encoding='utf-8')
z_new = open('test.bak','w',encoding='utf-8')
for line in z:
    if  '读数据' in line :
        line = line.replace('读数据','读需求文档')
    z_new.write(line)
z.close()
z_new.close()