Проблема в том, что вы передаете names вместе с dtypes аргументом.Это заставляет header действовать как None.Итак, рассмотрим:
In [1]: import pandas as pd, numpy as np
In [2]: dt={'serverTs': np.int32, 'FTs': np.int32}
In [3]: import io
In [4]: s = """FTs,serverTs
...: 0,1
...: 1,2
...: """
In [5]: pd.read_csv(io.StringIO(s))
Out[5]:
FTs serverTs
0 0 1
1 1 2
In [6]: pd.read_csv(io.StringIO(s), dtype=dt)
Out[6]:
FTs serverTs
0 0 1
1 1 2
Работает нормально.Однако, если я передам names:
In [8]: names = 'FTs','serverTs'
In [9]: pd.read_csv(io.StringIO(s), dtype=dt, names=names)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._convert_tokens()
TypeError: Cannot cast array from dtype('O') to dtype('int32') according to the rule 'safe'
During handling of the above exception, another exception occurred:
ValueError Traceback (most recent call last)
<ipython-input-9-18dcd5477b7e> in <module>()
----> 1 pd.read_csv(io.StringIO(s), dtype=dt, names=names)
/Users/juan/anaconda3/lib/python3.5/site-packages/pandas/io/parsers.py in parser_f(filepath_or_buffer, sep, delimiter, header, names, index_col, usecols, squeeze, prefix, mangle_dupe_cols, dtype, engine, converters, true_values, false_values, skipinitialspace, skiprows, nrows, na_values, keep_default_na, na_filter, verbose, skip_blank_lines, parse_dates, infer_datetime_format, keep_date_col, date_parser, dayfirst, iterator, chunksize, compression, thousands, decimal, lineterminator, quotechar, quoting, escapechar, comment, encoding, dialect, tupleize_cols, error_bad_lines, warn_bad_lines, skipfooter, skip_footer, doublequote, delim_whitespace, as_recarray, compact_ints, use_unsigned, low_memory, buffer_lines, memory_map, float_precision)
707 skip_blank_lines=skip_blank_lines)
708
--> 709 return _read(filepath_or_buffer, kwds)
710
711 parser_f.__name__ = name
/Users/juan/anaconda3/lib/python3.5/site-packages/pandas/io/parsers.py in _read(filepath_or_buffer, kwds)
453
454 try:
--> 455 data = parser.read(nrows)
456 finally:
457 parser.close()
/Users/juan/anaconda3/lib/python3.5/site-packages/pandas/io/parsers.py in read(self, nrows)
1067 raise ValueError('skipfooter not supported for iteration')
1068
-> 1069 ret = self._engine.read(nrows)
1070
1071 if self.options.get('as_recarray'):
/Users/juan/anaconda3/lib/python3.5/site-packages/pandas/io/parsers.py in read(self, nrows)
1837 def read(self, nrows=None):
1838 try:
-> 1839 data = self._reader.read(nrows)
1840 except StopIteration:
1841 if self._first_chunk:
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader.read()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._read_low_memory()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._read_rows()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._convert_column_data()
pandas/_libs/parsers.pyx in pandas._libs.parsers.TextReader._convert_tokens()
ValueError: invalid literal for int() with base 10: 'FTs'
In [10]:
Таким образом, одно из решений - передать правильный индекс заголовка:
In [10]: pd.read_csv(io.StringIO(s), dtype=dt, names=names, header=0)
Out[10]:
FTs serverTs
0 0 1
1 1 2
Или еще лучше, не пропустите namesВ любом случае, pandas все равно выведет это для вас:
In [11]: pd.read_csv(io.StringIO(s), dtype=dt)
Out[11]:
FTs serverTs
0 0 1
1 1 2