如以只读方式使用UTF-8编码方案读取tree.txt，并在读完之后关闭文件。
方法一：循环读取所有行
with
open
(
'tree.txt'
,
'r'
,
encoding
=
'utf-8'
)
as
f
:
for
line
in
f
:
print
(
line
)
f
.
close
(
)
方法二：先读取一行，再接着循环读取下面的所有行
with
open
(
'tree.txt'
,
'r'
,
encoding
=
'utf-8'
)
as
f
:
line
=
f
.
readline
(
)
print
(
line
)
while
(
line
)
:
line
=
f
.
readline
(
)
print
(
line
)
f
.
close
(
)
