def diff(arr, n, axis=0):
""" difference of n between self,
analagoust to s-s.shift(n) """
n = int(n)
na = np.nan
dtype = arr.dtype
is_timedelta = False
if needs_i8_conversion(arr):
dtype = np.float64
arr = arr.view('i8')
na = tslib.iNaT
is_timedelta = True
elif issubclass(dtype.type, np.integer):
dtype = np.float64
elif issubclass(dtype.type, np.bool_):
dtype = np.object_
dtype = np.dtype(dtype)
out_arr = np.empty(arr.shape, dtype=dtype)
na_indexer = [slice(None)] * arr.ndim
na_indexer[axis] = slice(None, n) if n >= 0 else slice(n, None)
out_arr[tuple(na_indexer)] = na
if arr.ndim == 2 and arr.dtype.name in _diff_special:
f = _diff_special[arr.dtype.name]
f(arr, out_arr, n, axis)
else:
res_indexer = [slice(None)] * arr.ndim
res_indexer[axis] = slice(n, None) if n >= 0 else slice(None, n)
res_indexer = tuple(res_indexer)
lag_indexer = [slice(None)] * arr.ndim
lag_indexer[axis] = slice(None, -n) if n > 0 else slice(-n, None)
lag_indexer = tuple(lag_indexer)
# need to make sure that we account for na for datelike/timedelta
# we don't actually want to subtract these i8 numbers
if is_timedelta:
res = arr[res_indexer]
lag = arr[lag_indexer]
mask = (arr[res_indexer] == na) | (arr[lag_indexer] == na)
if mask.any():
res = res.copy()
res[mask] = 0
lag = lag.copy()
lag[mask] = 0
result = res - lag
result[mask] = na
out_arr[res_indexer] = result
else:
out_arr[res_indexer] = arr[res_indexer] - arr[lag_indexer]
if is_timedelta:
from pandas import TimedeltaIndex
out_arr = TimedeltaIndex(out_arr.ravel().astype('int64')).asi8.reshape(
out_arr.shape).astype('timedelta64[ns]')
return out_arr
def diff(arr, n, axis=0):
""" difference of n between self,
analagoust to s-s.shift(n) """
n = int(n)
na = np.nan
dtype = arr.dtype
is_timedelta = False
if needs_i8_conversion(arr):
dtype = np.float64
arr = arr.view('i8')
na = tslib.iNaT
is_timedelta = True
elif issubclass(dtype.type, np.integer):
dtype = np.float64
elif issubclass(dtype.type, np.bool_):
dtype = np.object_
dtype = np.dtype(dtype)
out_arr = np.empty(arr.shape, dtype=dtype)
na_indexer = [slice(None)] * arr.ndim
na_indexer[axis] = slice(None, n) if n >= 0 else slice(n, None)
out_arr[tuple(na_indexer)] = na
if arr.ndim == 2 and arr.dtype.name in _diff_special:
f = _diff_special[arr.dtype.name]
f(arr, out_arr, n, axis)
else:
res_indexer = [slice(None)] * arr.ndim
res_indexer[axis] = slice(n, None) if n >= 0 else slice(None, n)
res_indexer = tuple(res_indexer)
lag_indexer = [slice(None)] * arr.ndim
lag_indexer[axis] = slice(None, -n) if n > 0 else slice(-n, None)
lag_indexer = tuple(lag_indexer)
# need to make sure that we account for na for datelike/timedelta
# we don't actually want to subtract these i8 numbers
if is_timedelta:
res = arr[res_indexer]
lag = arr[lag_indexer]
mask = (arr[res_indexer] == na) | (arr[lag_indexer] == na)
if mask.any():
res = res.copy()
res[mask] = 0
lag = lag.copy()
lag[mask] = 0
result = res - lag
result[mask] = na
out_arr[res_indexer] = result
else:
out_arr[res_indexer] = arr[res_indexer] - arr[lag_indexer]
if is_timedelta:
from pandas import TimedeltaIndex
out_arr = TimedeltaIndex(out_arr.ravel().astype('int64')).asi8.reshape(
out_arr.shape).astype('timedelta64[ns]')
return out_arr
