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DataFrame.astype(dtype, copy=True, errors='raise', **kwargs)[source]

Cast a pandas object to a specified dtype dtype.


dtype : data type, or dict of column name -> data type

Use a numpy.dtype or Python type to cast entire pandas object to the same type. Alternatively, use {col: dtype, …}, where col is a column label and dtype is a numpy.dtype or Python type to cast one or more of the DataFrame’s columns to column-specific types.

copy : bool, default True.

Return a copy when copy=True (be very careful setting copy=False as changes to values then may propagate to other pandas objects).

errors : {‘raise’, ‘ignore’}, default ‘raise’.

Control raising of exceptions on invalid data for provided dtype.

  • raise : allow exceptions to be raised
  • ignore : suppress exceptions. On error return original object

New in version 0.20.0.

raise_on_error : raise on invalid input

Deprecated since version 0.20.0: Use errors instead

kwargs : keyword arguments to pass on to the constructor


casted : type of caller

See also

Convert argument to datetime.
Convert argument to timedelta.
Convert argument to a numeric type.
Cast a numpy array to a specified type.


>>> ser = pd.Series([1, 2], dtype='int32')
>>> ser
0    1
1    2
dtype: int32
>>> ser.astype('int64')
0    1
1    2
dtype: int64

Convert to categorical type:

>>> ser.astype('category')
0    1
1    2
dtype: category
Categories (2, int64): [1, 2]

Convert to ordered categorical type with custom ordering:

>>> ser.astype('category', ordered=True, categories=[2, 1])
0    1
1    2
dtype: category
Categories (2, int64): [2 < 1]

Note that using copy=False and changing data on a new pandas object may propagate changes:

>>> s1 = pd.Series([1,2])
>>> s2 = s1.astype('int64', copy=False)
>>> s2[0] = 10
>>> s1  # note that s1[0] has changed too
0    10
1     2
dtype: int64
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