文件的增删改查

def delect():
    '删除一行信息'
# m = www.oldboy2.org
    while 1 :
        flag = False
        m = input('please input which url you want to delect:')
        with open('haproxy.conf',encoding = 'utf8') as f_read,open('delect','w',encoding = 'utf8') as f_write:
            for line in f_read:
                if line.startswith('backend')and m in line :
                    flag = True
                    continue
                if line.startswith('backend') and flag :
                    flag = False
                if flag :
                        continue
                f_write.write(line)
        if m == 'q':
            exit()
def select():
    '查找一行信息'
    #m = www.oldboy2.org
    while 3:
        m = input('please input which url you want to selet:')
        l = []
        flag = False
        with open('haproxy.conf', encoding='utf8')as f_read:
            for line in f_read:
                if line.startswith('backend') and m in line:
                    flag = True
                    continue
                if line.startswith('backend') and flag:
                    flag = False

                if flag:
                    l.append(line.strip())

        for i in l:
            print(i)
        if m == 'q':
            exit()
def insert():
    '增加一些信息'
    while 1:
        url =  input ('please input the url')
        ttt = input('please input what you what to insert:')
        with open('haproxy.conf', encoding='utf8')as f_read,open('insert','a',encoding = 'utf8')as f_write:
            for line in f_read:
                if line.startswith('backend') and url in line:
                    f_write.write(line)
                    f_write.write('\t\t'+ttt+'\n')
                else:
                    f_write.write(line)
        if url == 'q':
            exit()
def change():
    '改变某一行的信息'
    l = []
    flag = True
    while 1:
        url =  input ('please input the url:')
        with open('haproxy.conf', encoding='utf8')as f_read:
            for line in f_read:

                if line.startswith('backend') and url in line:
                    flag = False
                    continue
                if line.startswith('backend') and flag == False:
                    flag = True
                if flag == False:
                    l.append(line.strip())
        print(l)
        ttt = input('please input what you what to change:')
        ccc = input('please input what you want to write:')
        l[l.index(ttt)]= ccc
        with open('haproxy.conf', encoding='utf8')as f_read,open('change', 'a', encoding='utf8')as f_write:
            for line in f_read:

                if ttt in line:
                    f_write.write(ccc+'\n')
                    continue
                f_write.write(line)
        if url == 'q':
            exit()
def tell_msg():
    print("""
       ********************
        删除 : delect
        查找 : select
        增加 : insert
        改变 : change
       ********************
    """ )
msg = {
    'delect':delect,
    'select':select,
    'insert':insert,
    'change':change
}
def main():
    tell_msg()
    m = input('please input your choice:')
    msg[m]()
    if m == 'q':
        exit()
main()