Python3 寫入文件

Demo:

file = open("test.txt", "wb")
file.write("string")

上面這段代碼運行會報類型錯誤：TypeError: a bytes-like object is required, not 'str' 

wirte方法是將一個字節緩沖區寫入到目標文件中，而不支持string類型

write源碼：

def write(self, *args, **kwargs): # real signature unknown
    """
    Write buffer b to file, return number of bytes written.
    
    Only makes one system call, so not all of the data may be written.
    The number of bytes actually written is returned.  In non-blocking mode,
    returns None if the write would block.
    """
    pass

注：python3 將字符串寫入到目標文件時，必須先將字符串轉換為字節才能寫入，python2可以直接將字符串寫入到目標文件中