numpy.fromregex

numpy.fromregex(file, regexp, dtype, encoding=None)[源代码]

Construct an array from a text file, using regular expression parsing.

The returned array is always a structured array, and is constructed from all matches of the regular expression in the file. Groups in the regular expression are converted to fields of the structured array.

Parameters:
file : str or file

File name or file object to read.

regexp : str or regexp

Regular expression used to parse the file. Groups in the regular expression correspond to fields in the dtype.

dtype : dtype or list of dtypes

Dtype for the structured array.

encoding : str, optional

Encoding used to decode the inputfile. Does not apply to input streams.

1.14.0 新版功能.

Returns:
output : ndarray

The output array, containing the part of the content of file that was matched by regexp. output is always a structured array.

Raises:
TypeError

When dtype is not a valid dtype for a structured array.

Notes

Dtypes for structured arrays can be specified in several forms, but all forms specify at least the data type and field name. For details see doc.structured_arrays.

Examples

>>> f = open('test.dat', 'w')
>>> f.write("1312 foo\n1534  bar\n444   qux")
>>> f.close()
>>> regexp = r"(\d+)\s+(...)"  # match [digits, whitespace, anything]
>>> output = np.fromregex('test.dat', regexp,
...                       [('num', np.int64), ('key', 'S3')])
>>> output
array([(1312L, 'foo'), (1534L, 'bar'), (444L, 'qux')],
      dtype=[('num', '<i8'), ('key', '|S3')])
>>> output['num']
array([1312, 1534,  444], dtype=int64)