读取整个文件：

with open(‘a.txt‘) as file_object:
    file_read = file_object.read()
    print(file_read)

f = open(‘a.txt‘)
print(f.read())
f.close()

逐行读取文件：

file_name = (‘a.txt‘)
with open(file_name) as file_object:
    for line in file_object:
        print(line.rstrip())                   rstrip去除尾部空格

file_name = (‘a.txt‘)
with open(file_name) as file_object:
    lines = file_object.readlines()

for line in lines:
    print(line.rstrip())

file_name = (‘a.txt‘)
with open(file_name) as file_object:
    lines = file_object.readlines()
pi_string = ‘‘
for line in lines:
    pi_string += line.rstrip()
    print (len(line))
print(pi_string)
print(len(pi_string))

file_name = (‘a.txt‘)
with open(file_name) as file_object:
    lines = file_object.readlines()
pi_string = ‘‘
for line in lines:
    pi_string += line.strip()

print(pi_string[:100] + ‘...‘)

print(len(pi_string))


如遇到字符集问题：

with open(‘a.txt‘,encoding=‘utf-8‘,errors=‘ignore‘) as f:
    file_object = f.readlines()

for line in file_object:
    print(line.rstrip())




写入：

file_name = ‘a.txt‘
with open(file_name,‘w‘,encoding=‘utf-8‘) as f:
    f.write(‘i love you‘)
    f.write(‘\ni love zhangyiyi‘)

追加到末尾：

file_name = ‘a.txt‘
with open(file_name,‘a‘,encoding=‘utf-8‘) as f:
    f.write(‘\ni love you‘)
    f.write(‘\ni love zhangyiyi‘)


异常处理:

try:
    print(5/0)
except ZeroDivisionError:
    print("输入错误")

while True:
    first_number = input(‘\nfirst number?:‘)
    if first_number == ‘q‘:
        break
    second_number = input("second number:")
    try:
        answer = int(first_number) / int(second_number)
    except Exception:
        print("错误")
    else:
        print(answer)

文件异常：

file_name = ‘c.txt‘
try:
    with open(file_name,encoding=‘utf-8‘) as f:
        contents = f.read()
except FileNotFoundError:
    msg = "文件不存在"
    print(msg)

2017-5-17 文件异常