def iterhashrightjoin(left, right, lkey, rkey, missing, llookup, lprefix,
rprefix):
lit = iter(left)
rit = iter(right)
lhdr = next(lit)
rhdr = next(rit)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from left table
rgetk = operator.itemgetter(*rkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(text_type(lprefix) + text_type(f)) for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(text_type(rprefix) + text_type(f))
for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join rows
def joinrows(_rrow, _lrows):
for lrow in _lrows:
# start with the left row
_outrow = list(lrow)
# extend with non-key values from the right row
_outrow.extend(rgetv(_rrow))
yield tuple(_outrow)
for rrow in rit:
k = rgetk(rrow)
if k in llookup:
lrows = llookup[k]
for outrow in joinrows(rrow, lrows):
yield outrow
else:
# start with missing values in place of the left row
outrow = [missing] * len(lhdr)
# set key values
for li, ri in zip(lkind, rkind):
outrow[li] = rrow[ri]
# extend with non-key values from the right row
outrow.extend(rgetv(rrow))
yield tuple(outrow)
def iterhashrightjoin(left, right, lkey, rkey, missing, llookup, lprefix,
rprefix):
lit = iter(left)
rit = iter(right)
lhdr = next(lit)
rhdr = next(rit)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from left table
rgetk = operator.itemgetter(*rkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(str(lprefix) + str(f))
for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(str(rprefix) + str(f)) for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join rows
def joinrows(_rrow, _lrows):
for lrow in _lrows:
# start with the left row
_outrow = list(lrow)
# extend with non-key values from the right row
_outrow.extend(rgetv(_rrow))
yield tuple(_outrow)
for rrow in rit:
k = rgetk(rrow)
if k in llookup:
lrows = llookup[k]
for outrow in joinrows(rrow, lrows):
yield outrow
else:
# start with missing values in place of the left row
outrow = [missing] * len(lhdr)
# set key values
for li, ri in zip(lkind, rkind):
outrow[li] = rrow[ri]
# extend with non-key values from the right row
outrow.extend(rgetv(rrow))
yield tuple(outrow)
def iterhashlookupjoin(left, right, lkey, rkey, missing, lprefix, rprefix):
lit = iter(left)
lhdr = next(lit)
rhdr, rit = iterpeek(right) # need the whole lot to pass to lookup
rlookup = lookupone(rit, rkey, strict=False)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from left table
lgetk = operator.itemgetter(*lkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(str(lprefix) + str(f))
for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(str(rprefix) + str(f))
for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join rows
def joinrows(_lrow, _rrow):
# start with the left row
_outrow = list(_lrow)
# extend with non-key values from the right row
_outrow.extend(rgetv(_rrow))
return tuple(_outrow)
for lrow in lit:
k = lgetk(lrow)
if k in rlookup:
rrow = rlookup[k]
yield joinrows(lrow, rrow)
else:
outrow = list(lrow) # start with the left row
# extend with missing values in place of the right row
outrow.extend([missing] * len(rvind))
yield tuple(outrow)
def iterhashlookupjoin(left, right, lkey, rkey, missing, lprefix, rprefix):
lit = iter(left)
lhdr = next(lit)
rhdr, rit = iterpeek(right) # need the whole lot to pass to lookup
rlookup = lookupone(rit, rkey, strict=False)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from left table
lgetk = operator.itemgetter(*lkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(text_type(lprefix) + text_type(f)) for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(text_type(rprefix) + text_type(f))
for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join rows
def joinrows(_lrow, _rrow):
# start with the left row
_outrow = list(_lrow)
# extend with non-key values from the right row
_outrow.extend(rgetv(_rrow))
return tuple(_outrow)
for lrow in lit:
k = lgetk(lrow)
if k in rlookup:
rrow = rlookup[k]
yield joinrows(lrow, rrow)
else:
outrow = list(lrow) # start with the left row
# extend with missing values in place of the right row
outrow.extend([missing] * len(rvind))
yield tuple(outrow)
def iterhashjoin(left, right, lkey, rkey, rlookup, lprefix, rprefix):
lit = iter(left)
rit = iter(right)
lhdr = next(lit)
rhdr = next(rit)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from left table
lgetk = operator.itemgetter(*lkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(str(lprefix) + str(f)) for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(str(rprefix) + str(f)) for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join rows
def joinrows(_lrow, _rrows):
for rrow in _rrows:
# start with the left row
_outrow = list(_lrow)
# extend with non-key values from the right row
_outrow.extend(rgetv(rrow))
yield tuple(_outrow)
for lrow in lit:
k = lgetk(lrow)
if k in rlookup:
rrows = rlookup[k]
for outrow in joinrows(lrow, rrows):
yield outrow
def itermelt(source, key, variables, variablefield, valuefield):
if key is None and variables is None:
raise ValueError('either key or variables must be specified')
it = iter(source)
hdr = next(it)
# determine key and variable field indices
key_indices = variables_indices = None
if key is not None:
key_indices = asindices(hdr, key)
if variables is not None:
if not isinstance(variables, (list, tuple)):
variables = (variables,)
variables_indices = asindices(hdr, variables)
if key is None:
# assume key is fields not in variables
key_indices = [i for i in range(len(hdr))
if i not in variables_indices]
if variables is None:
# assume variables are fields not in key
variables_indices = [i for i in range(len(hdr))
if i not in key_indices]
variables = [hdr[i] for i in variables_indices]
getkey = rowgetter(*key_indices)
# determine the output fields
outhdr = [hdr[i] for i in key_indices]
outhdr.append(variablefield)
outhdr.append(valuefield)
yield tuple(outhdr)
# construct the output data
for row in it:
k = getkey(row)
for v, i in zip(variables, variables_indices):
try:
o = list(k) # populate with key values initially
o.append(v) # add variable
o.append(row[i]) # add value
yield tuple(o)
except IndexError:
# row is missing this value, and melt() should yield no row
pass
def __iter__(self):
it = iter(self.table)
hdr = next(it)
shdr = sorted(hdr)
indices = asindices(hdr, shdr)
transform = rowgetter(*indices)
# yield the transformed header
yield tuple(shdr)
# construct the transformed data
missing = self.missing
for row in it:
try:
yield transform(row)
except IndexError:
# row is short, let's be kind and fill in any missing fields
yield tuple(row[i] if i < len(row) else missing
for i in indices)
def __iter__(self):
it = iter(self.table)
hdr = next(it)
shdr = sorted(hdr)
indices = asindices(hdr, shdr)
transform = rowgetter(*indices)
# yield the transformed header
yield tuple(shdr)
# construct the transformed data
missing = self.missing
for row in it:
try:
yield transform(row)
except IndexError:
# row is short, let's be kind and fill in any missing fields
yield tuple(row[i] if i < len(row) else missing
for i in indices)
def itermelt(source, key, variables, variablefield, valuefield):
it = iter(source)
# normalise some stuff
hdr = next(it)
flds = list(map(text_type, hdr))
if key and not isinstance(key, (list, tuple)):
key = (key,) # normalise to a tuple
if variables and not isinstance(variables, (list, tuple)):
# shouldn't expect this, but ... ?
variables = (variables,) # normalise to a tuple
if not key:
# assume key is fields not in variables
key = [f for f in flds if f not in variables]
if not variables:
# assume variables are fields not in key
variables = [f for f in flds if f not in key]
# determine the output fields
outhdr = list(key)
outhdr.append(variablefield)
outhdr.append(valuefield)
yield tuple(outhdr)
key_indices = [flds.index(k) for k in key]
getkey = rowgetter(*key_indices)
variables_indices = [flds.index(v) for v in variables]
# construct the output data
for row in it:
k = getkey(row)
for v, i in zip(variables, variables_indices):
try:
o = list(k) # populate with key values initially
o.append(v) # add variable
o.append(row[i]) # add value
yield tuple(o)
except IndexError:
# row is missing this value, and melt() should yield no row
pass
def _setup_lookup(table, key, value):
# obtain iterator and header row
it = iter(table)
hdr = next(it)
# prepare key getter
keyindices = asindices(hdr, key)
assert len(keyindices) > 0, 'no key selected'
getkey = operator.itemgetter(*keyindices)
# prepare value getter
if value is None:
# default value is complete row
getvalue = rowgetter(*range(len(hdr)))
else:
valueindices = asindices(hdr, value)
assert len(valueindices) > 0, 'no value selected'
getvalue = operator.itemgetter(*valueindices)
return it, getkey, getvalue
def itercut(source, spec, missing=None):
it = iter(source)
spec = tuple(spec) # make sure no-one can change midstream
# convert field selection into field indices
hdr = next(it)
indices = asindices(hdr, spec)
# define a function to transform each row in the source data
# according to the field selection
transform = rowgetter(*indices)
# yield the transformed header
yield transform(hdr)
# construct the transformed data
for row in it:
try:
yield transform(row)
except IndexError:
# row is short, let's be kind and fill in any missing fields
yield tuple(row[i] if i < len(row) else missing for i in indices)
def itercut(source, spec, missing=None):
it = iter(source)
spec = tuple(spec) # make sure no-one can change midstream
# convert field selection into field indices
hdr = next(it)
indices = asindices(hdr, spec)
# define a function to transform each row in the source data
# according to the field selection
transform = rowgetter(*indices)
# yield the transformed header
yield transform(hdr)
# construct the transformed data
for row in it:
try:
yield transform(row)
except IndexError:
# row is short, let's be kind and fill in any missing fields
yield tuple(row[i] if i < len(row) else missing for i in indices)
def __iter__(self):
it = iter(self.table)
# determine output fields
hdr = next(it)
outhdr = [f for f in hdr if f != self.field]
outhdr.insert(self.index, self.field)
yield tuple(outhdr)
# define a function to transform each row in the source data
# according to the field selection
outflds = list(map(str, outhdr))
indices = asindices(hdr, outflds)
transform = rowgetter(*indices)
# construct the transformed data
for row in it:
try:
yield transform(row)
except IndexError:
# row is short, let's be kind and fill in any missing fields
yield tuple(row[i] if i < len(row) else self.missing
for i in indices)
def __iter__(self):
it = iter(self.table)
# determine output fields
hdr = next(it)
outhdr = [f for f in hdr if f != self.field]
outhdr.insert(self.index, self.field)
yield tuple(outhdr)
# define a function to transform each row in the source data
# according to the field selection
outflds = list(map(str, outhdr))
indices = asindices(hdr, outflds)
transform = rowgetter(*indices)
# construct the transformed data
for row in it:
try:
yield transform(row)
except IndexError:
# row is short, let's be kind and fill in any missing fields
yield tuple(row[i] if i < len(row) else self.missing
for i in indices)
def iterlookupjoin(left,
right,
lkey,
rkey,
missing=None,
lprefix=None,
rprefix=None):
lit = iter(left)
rit = iter(right)
lhdr = next(lit)
rhdr = next(rit)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from both tables
lgetk = operator.itemgetter(*lkind)
rgetk = operator.itemgetter(*rkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(text_type(lprefix) + text_type(f)) for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(text_type(rprefix) + text_type(f))
for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join two groups of rows
def joinrows(_lrowgrp, _rrowgrp):
if _rrowgrp is None:
for lrow in _lrowgrp:
outrow = list(lrow) # start with the left row
# extend with missing values in place of the right row
outrow.extend([missing] * len(rvind))
yield tuple(outrow)
else:
rrow = next(iter(_rrowgrp)) # pick first arbitrarily
for lrow in _lrowgrp:
# start with the left row
outrow = list(lrow)
# extend with non-key values from the right row
outrow.extend(rgetv(rrow))
yield tuple(outrow)
# construct group iterators for both tables
lgit = itertools.groupby(lit, key=lgetk)
rgit = itertools.groupby(rit, key=rgetk)
lrowgrp = []
# loop until *either* of the iterators is exhausted
lkval, rkval = None, None # initialise here to handle empty tables
try:
# pick off initial row groups
lkval, lrowgrp = next(lgit)
rkval, rrowgrp = next(rgit)
while True:
if lkval < rkval:
for row in joinrows(lrowgrp, None):
yield tuple(row)
# advance left
lkval, lrowgrp = next(lgit)
elif lkval > rkval:
# advance right
rkval, rrowgrp = next(rgit)
else:
for row in joinrows(lrowgrp, rrowgrp):
yield tuple(row)
# advance both
lkval, lrowgrp = next(lgit)
rkval, rrowgrp = next(rgit)
except StopIteration:
pass
# make sure any left rows remaining are yielded
if lkval > rkval:
# yield anything that got left hanging
for row in joinrows(lrowgrp, None):
yield tuple(row)
# yield the rest
for lkval, lrowgrp in lgit:
for row in joinrows(lrowgrp, None):
yield tuple(row)
def iterlookupjoin(left, right, lkey, rkey, missing=None, lprefix=None,
rprefix=None):
lit = iter(left)
rit = iter(right)
lhdr = next(lit)
rhdr = next(rit)
# determine indices of the key fields in left and right tables
lkind = asindices(lhdr, lkey)
rkind = asindices(rhdr, rkey)
# construct functions to extract key values from both tables
lgetk = operator.itemgetter(*lkind)
rgetk = operator.itemgetter(*rkind)
# determine indices of non-key fields in the right table
# (in the output, we only include key fields from the left table - we
# don't want to duplicate fields)
rvind = [i for i in range(len(rhdr)) if i not in rkind]
rgetv = rowgetter(*rvind)
# determine the output fields
if lprefix is None:
outhdr = list(lhdr)
else:
outhdr = [(str(lprefix) + str(f)) for f in lhdr]
if rprefix is None:
outhdr.extend(rgetv(rhdr))
else:
outhdr.extend([(str(rprefix) + str(f)) for f in rgetv(rhdr)])
yield tuple(outhdr)
# define a function to join two groups of rows
def joinrows(_lrowgrp, _rrowgrp):
if _rrowgrp is None:
for lrow in _lrowgrp:
outrow = list(lrow) # start with the left row
# extend with missing values in place of the right row
outrow.extend([missing] * len(rvind))
yield tuple(outrow)
else:
rrow = next(iter(_rrowgrp)) # pick first arbitrarily
for lrow in _lrowgrp:
# start with the left row
outrow = list(lrow)
# extend with non-key values from the right row
outrow.extend(rgetv(rrow))
yield tuple(outrow)
# construct group iterators for both tables
lgit = itertools.groupby(lit, key=lgetk)
rgit = itertools.groupby(rit, key=rgetk)
lrowgrp = []
# loop until *either* of the iterators is exhausted
lkval, rkval = None, None # initialise here to handle empty tables
try:
# pick off initial row groups
lkval, lrowgrp = next(lgit)
rkval, rrowgrp = next(rgit)
while True:
if lkval < rkval:
for row in joinrows(lrowgrp, None):
yield tuple(row)
# advance left
lkval, lrowgrp = next(lgit)
elif lkval > rkval:
# advance right
rkval, rrowgrp = next(rgit)
else:
for row in joinrows(lrowgrp, rrowgrp):
yield tuple(row)
# advance both
lkval, lrowgrp = next(lgit)
rkval, rrowgrp = next(rgit)
except StopIteration:
pass
# make sure any left rows remaining are yielded
if lkval > rkval:
# yield anything that got left hanging
for row in joinrows(lrowgrp, None):
yield tuple(row)
# yield the rest
for lkval, lrowgrp in lgit:
for row in joinrows(lrowgrp, None):
yield tuple(row)
