def dataframe_to_thrift_struct(df, name, roffset, coffset, rows, cols, format):
"""
:type df: pandas.core.frame.DataFrame
:type name: str
:type coffset: int
:type roffset: int
:type rows: int
:type cols: int
:type format: str
"""
dim = len(df.axes)
num_rows = df.shape[0]
num_cols = df.shape[1] if dim > 1 else 1
array_chunk = GetArrayResponse()
array_chunk.slice = name
array_chunk.rows = num_rows
array_chunk.cols = num_cols
array_chunk.format = ""
array_chunk.type = ""
array_chunk.bounds = (0, 0)
if (rows, cols) == (-1, -1):
rows, cols = num_rows, num_cols
rows = min(rows, MAXIMUM_ARRAY_SIZE)
cols = min(cols, MAXIMUM_ARRAY_SIZE, num_cols)
# need to precompute column bounds here before slicing!
col_bounds = [None] * cols
dtypes = [None] * cols
if dim > 1:
for col in range(cols):
dtype = df.dtypes.iloc[coffset + col].kind
dtypes[col] = dtype
if dtype in "biufc":
cvalues = df.iloc[:, coffset + col]
bounds = (cvalues.min(), cvalues.max())
else:
bounds = (0, 0)
col_bounds[col] = bounds
else:
dtype = df.dtype.kind
dtypes[0] = dtype
col_bounds[0] = (df.min(), df.max()) if dtype in "biufc" else (0, 0)
df = df.iloc[roffset:roffset + rows, coffset:coffset +
cols] if dim > 1 else df.iloc[roffset:roffset + rows]
rows = df.shape[0]
cols = df.shape[1] if dim > 1 else 1
format = format.replace('%', '')
def col_to_format(c):
return format if dtypes[c] == 'f' and format else array_default_format(
dtypes[c])
array_chunk.headers = header_data_to_thrift_struct(rows, cols, dtypes,
col_bounds,
col_to_format, df, dim)
array_chunk.data = array_data_to_thrift_struct(
rows, cols, lambda r: (("%" + col_to_format(c)) %
(df.iat[r, c] if dim > 1 else df.iat[r])
for c in range(cols)))
return array_chunk
def array_to_meta_thrift_struct(array, name, format):
type = array.dtype.kind
slice = name
l = len(array.shape)
# initial load, compute slice
if format == '%':
if l > 2:
slice += '[0]' * (l - 2)
for r in range(l - 2):
array = array[0]
if type == 'f':
format = '.5f'
elif type == 'i' or type == 'u':
format = 'd'
else:
format = 's'
else:
format = format.replace('%', '')
l = len(array.shape)
reslice = ""
if l > 2:
raise Exception("%s has more than 2 dimensions." % slice)
elif l == 1:
# special case with 1D arrays arr[i, :] - row, but arr[:, i] - column with equal shape and ndim
# http://stackoverflow.com/questions/16837946/numpy-a-2-rows-1-column-file-loadtxt-returns-1row-2-columns
# explanation: http://stackoverflow.com/questions/15165170/how-do-i-maintain-row-column-orientation-of-vectors-in-numpy?rq=1
# we use kind of a hack - get information about memory from C_CONTIGUOUS
is_row = array.flags['C_CONTIGUOUS']
if is_row:
rows = 1
cols = len(array)
if cols < len(array):
reslice = '[0:%s]' % (cols)
array = array[0:cols]
else:
cols = 1
rows = len(array)
if rows < len(array):
reslice = '[0:%s]' % (rows)
array = array[0:rows]
elif l == 2:
rows = array.shape[-2]
cols = array.shape[-1]
if cols < array.shape[-1] or rows < array.shape[-2]:
reslice = '[0:%s, 0:%s]' % (rows, cols)
array = array[0:rows, 0:cols]
# avoid slice duplication
if not slice.endswith(reslice):
slice += reslice
bounds = (0, 0)
if type in "biufc":
bounds = (array.min(), array.max())
array_chunk = GetArrayResponse()
array_chunk.slice = slice
array_chunk.rows = rows
array_chunk.cols = cols
array_chunk.format = format
array_chunk.type = type
array_chunk.bounds = bounds
return array, array_chunk, rows, cols, format