with open和open

with open和open的区别在于，使用with open可以自动关闭文件，而使用open需要手动关闭文件。with open的语法如下：

with open('file.txt', 'r') as f:
    # do something with f

而open的语法如下：

f = open('file.txt', 'r')
# do something with f
.close()