writers.py 文件源码

def __init__(self, fields, field_prefix=None):
        """
        Initializes a new TSV writer

        The first value of each fields tuple is the destination field name.
        The second value is a str property path (e.g. "one.two.three") or
        a callable that when passed a row returns a computed field value

        Arguments:
            fields (List): list of (str, str|callable) tuples
            field_prefix (str): path prefix to prefix field lookups with
        """
        self.fields = OrderedDict(fields)
        self.columns = self.fields.keys()
        self.field_mappers = {column: self.get_field_mapper(field) for (column, field) in fields}
        self.prefix_mapper = attrgetter(field_prefix) if field_prefix is not None else None