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python with...As

with open('abc.txt', 'r') as f: balabalabala 等价于 try: f = open('abc.txt', 'r') except: pass else: balabalabala finally: f.close() 语法是不是简洁多了?

with open('abc.txt','r') as f: balabalabala 等价于 try: f = open('abc.txt','r') except: pass else: balabalabala finally: f.close() 语法是不是简洁多了?

比如打开一个文件 with open (filename,'r') as fp: for line in fp: print line with语句主要是实现打开和关闭简写为一条语句,上面的例子在for循环完成后 文件自动关闭

改变量名,不要把变量名和关键字重名,变量名前可加_来区分,比如_type = "xxx"

astype实现变量类型转换: astype(type): returns a copy of the array converted to the specified type. a = a.astype('Float64') b = b.astype('Int32')

方法a要通过一实例来调用,如: class A: def a(self): print("I'm a") obj = A() obj.a()

这个是因为pythonwin的工作目录不是当前目录。 这是刚学习使用集成环境,或者是编辑器时经常发生的事情。 你只需要将'usemodule.py'改成绝对目录就可以了。 比如 某某盘符下的某个目录下的,某个文件。

翻译如下 as with 如同,和-----一样,就----而言, 例句 As with many technological revolutions, you are unlikely to beaware of it 就像诸多的技术革命一样,你可能不太会注意到它。

文件权限没打开?

try: with open("path/to/filename.file", "r") as f: pass # do with file handleexcept Exception as e: print(e) # do with exception

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