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2026-07-13 13:21:43 +08:00

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Python

"""Basic function to preprocess tabular data before assembling it in a `DataLoaders`.
Docs: https://docs.fast.ai/tabular.core.html.md"""
# AUTOGENERATED! DO NOT EDIT! File to edit: ../../nbs/40_tabular.core.ipynb.
# %% auto #0
__all__ = ['make_date', 'add_datepart', 'add_elapsed_times', 'cont_cat_split', 'df_shrink_dtypes', 'df_shrink', 'Tabular',
'TabularPandas', 'TabularProc', 'Categorify', 'FillStrategy', 'FillMissing', 'ReadTabBatch', 'show_batch',
'TabDataLoader', 'TabWeightedDL']
# %% ../../nbs/40_tabular.core.ipynb #7bf25495
from ..torch_basics import *
from ..data.all import *
# %% ../../nbs/40_tabular.core.ipynb #2638ab5a
pd.set_option('mode.chained_assignment','raise')
# %% ../../nbs/40_tabular.core.ipynb #0bbabf95
def make_date(df, date_field):
"Make sure `df[date_field]` is of the right date type."
field_dtype = df[date_field].dtype
if isinstance(field_dtype, pd.core.dtypes.dtypes.DatetimeTZDtype):
field_dtype = np.datetime64
if not isinstance(field_dtype, np.dtype) or not np.issubdtype(field_dtype, np.datetime64):
df[date_field] = pd.to_datetime(df[date_field])
# %% ../../nbs/40_tabular.core.ipynb #2731eac6
def add_datepart(df, field_name, prefix=None, drop=True, time=False):
"Helper function that adds columns relevant to a date in the column `field_name` of `df`."
make_date(df, field_name)
field = df[field_name]
prefix = ifnone(prefix, re.sub('[Dd]ate$', '', field_name))
attr = ['Year', 'Month', 'Week', 'Day', 'Dayofweek', 'Dayofyear', 'Is_month_end', 'Is_month_start',
'Is_quarter_end', 'Is_quarter_start', 'Is_year_end', 'Is_year_start']
if time: attr = attr + ['Hour', 'Minute', 'Second']
# Pandas removed `dt.week` in v1.1.10
week = field.dt.isocalendar().week.astype(field.dt.day.dtype) if hasattr(field.dt, 'isocalendar') else field.dt.week
for n in attr: df[prefix + n] = getattr(field.dt, n.lower()) if n != 'Week' else week
mask = ~field.isna()
df[prefix + 'Elapsed'] = np.where(mask,field.values.astype(np.int64) // 10 ** 9,np.nan)
if drop: df.drop(field_name, axis=1, inplace=True)
return df
# %% ../../nbs/40_tabular.core.ipynb #4d78de59
def _get_elapsed(df,field_names, date_field, base_field, prefix):
for f in field_names:
day1 = np.timedelta64(1, 'D')
last_date,last_base,res = np.datetime64(),None,[]
for b,v,d in zip(df[base_field].values, df[f].values, df[date_field].values):
if last_base is None or b != last_base:
last_date,last_base = np.datetime64(),b
if v: last_date = d
res.append(((d-last_date).astype('timedelta64[D]') / day1))
df[prefix + f] = res
return df
# %% ../../nbs/40_tabular.core.ipynb #e3901ffe
def add_elapsed_times(df, field_names, date_field, base_field):
"Add in `df` for each event in `field_names` the elapsed time according to `date_field` grouped by `base_field`"
field_names = list(L(field_names))
#Make sure date_field is a date and base_field a bool
df[field_names] = df[field_names].astype('bool')
make_date(df, date_field)
work_df = df[field_names + [date_field, base_field]]
work_df = work_df.sort_values([base_field, date_field])
work_df = _get_elapsed(work_df, field_names, date_field, base_field, 'After')
work_df = work_df.sort_values([base_field, date_field], ascending=[True, False])
work_df = _get_elapsed(work_df, field_names, date_field, base_field, 'Before')
for a in ['After' + f for f in field_names] + ['Before' + f for f in field_names]:
work_df[a] = work_df[a].fillna(0).astype(int)
for a,s in zip([True, False], ['_bw', '_fw']):
work_df = work_df.set_index(date_field)
tmp = (work_df[[base_field] + field_names].sort_index(ascending=a)
.groupby(base_field).rolling(7, min_periods=1).sum())
if base_field in tmp: tmp.drop(base_field, axis=1,inplace=True)
tmp.reset_index(inplace=True)
work_df.reset_index(inplace=True)
work_df = work_df.merge(tmp, 'left', [date_field, base_field], suffixes=['', s])
work_df.drop(field_names, axis=1, inplace=True)
return df.merge(work_df, 'left', [date_field, base_field])
# %% ../../nbs/40_tabular.core.ipynb #6086b66b
def cont_cat_split(df, max_card=20, dep_var=None):
"Helper function that returns column names of cont and cat variables from given `df`."
cont_names, cat_names = [], []
for label in df:
if label in L(dep_var): continue
if ((pd.api.types.is_integer_dtype(df[label].dtype) and
df[label].unique().shape[0] > max_card) or
pd.api.types.is_float_dtype(df[label].dtype)):
cont_names.append(label)
else: cat_names.append(label)
return cont_names, cat_names
# %% ../../nbs/40_tabular.core.ipynb #9a3b6c97
def df_shrink_dtypes(df, skip=[], obj2cat=True, int2uint=False):
"Return any possible smaller data types for DataFrame columns. Allows `object`->`category`, `int`->`uint`, and exclusion."
# 1: Build column filter and typemap
excl_types, skip = {'category','datetime64[ns]','bool'}, set(skip)
typemap = {'int' : [(np.dtype(x), np.iinfo(x).min, np.iinfo(x).max) for x in (np.int8, np.int16, np.int32, np.int64)],
'uint' : [(np.dtype(x), np.iinfo(x).min, np.iinfo(x).max) for x in (np.uint8, np.uint16, np.uint32, np.uint64)],
'float' : [(np.dtype(x), np.finfo(x).min, np.finfo(x).max) for x in (np.float32, np.float64, np.longdouble)]
}
if obj2cat: typemap['object'] = typemap['str'] = 'category'
else: excl_types.update({'object', 'str'})
new_dtypes = {}
exclude = lambda dt: dt[1].name not in excl_types and dt[0] not in skip
for c, old_t in filter(exclude, df.dtypes.items()):
t = next((v for k,v in typemap.items() if old_t.name.startswith(k)), None)
if isinstance(t, list): # Find the smallest type that fits
if int2uint and t==typemap['int'] and df[c].min() >= 0: t=typemap['uint']
new_t = next((r[0] for r in t if r[1]<=df[c].min() and r[2]>=df[c].max()), None)
if new_t and new_t == old_t: new_t = None
else: new_t = t if isinstance(t, str) else None
if new_t: new_dtypes[c] = new_t
return new_dtypes
# %% ../../nbs/40_tabular.core.ipynb #a97f5143
def df_shrink(df, skip=[], obj2cat=True, int2uint=False):
"Reduce DataFrame memory usage, by casting to smaller types returned by `df_shrink_dtypes()`."
dt = df_shrink_dtypes(df, skip, obj2cat=obj2cat, int2uint=int2uint)
return df.astype(dt)
# %% ../../nbs/40_tabular.core.ipynb #d3046984
class _TabIloc:
"Get/set rows by iloc and cols by name"
def __init__(self,to): self.to = to
def __getitem__(self, idxs):
df = self.to.items
if isinstance(idxs,tuple):
rows,cols = idxs
cols = df.columns.isin(cols) if is_listy(cols) else df.columns.get_loc(cols)
else: rows,cols = idxs,slice(None)
return self.to.new(df.iloc[rows, cols])
# %% ../../nbs/40_tabular.core.ipynb #498b3f92
class Tabular(CollBase, GetAttr, FilteredBase):
"A `DataFrame` wrapper that knows which cols are cont/cat/y, and returns rows in `__getitem__`"
_default,with_cont='procs',True
def __init__(self, df, procs=None, cat_names=None, cont_names=None, y_names=None, y_block=None, splits=None,
do_setup=True, device=None, inplace=False, reduce_memory=True):
if inplace and splits is not None and pd.options.mode.chained_assignment is not None:
warn("Using inplace with splits will trigger a pandas error. Set `pd.options.mode.chained_assignment=None` to avoid it.")
if not inplace: df = df.copy()
if reduce_memory: df = df_shrink(df)
if splits is not None: df = df.iloc[sum(splits, [])]
self.dataloaders = delegates(self._dl_type.__init__)(self.dataloaders)
super().__init__(df)
self.y_names,self.device = L(y_names),device
if y_block is None and self.y_names:
# Make ys categorical if they're not numeric
ys = df[self.y_names]
if len(ys.select_dtypes(include='number').columns)!=len(ys.columns): y_block = CategoryBlock()
else: y_block = RegressionBlock()
if y_block is not None and do_setup:
if callable(y_block): y_block = y_block()
procs = L(procs) + y_block.type_tfms
self.cat_names,self.cont_names,self.procs = L(cat_names),L(cont_names),Pipeline(procs)
self.split = len(df) if splits is None else len(splits[0])
if do_setup: self.setup()
def new(self, df, inplace=False):
return type(self)(df, do_setup=False, reduce_memory=False, y_block=TransformBlock(), inplace=inplace,
**attrdict(self, 'procs','cat_names','cont_names','y_names', 'device'))
def subset(self, i): return self.new(self.items[slice(0,self.split) if i==0 else slice(self.split,len(self))])
def copy(self): self.items = self.items.copy(); return self
def decode(self): return self.procs.decode(self)
def decode_row(self, row): return self.new(pd.DataFrame(row).T).decode().items.iloc[0]
def show(self, max_n=10, **kwargs): display_df(self.new(self.all_cols[:max_n]).decode().items)
def setup(self): self.procs.setup(self)
def process(self): self.procs(self)
def loc(self): return self.items.loc
def iloc(self): return _TabIloc(self)
def targ(self): return self.items[self.y_names]
def x_names (self): return self.cat_names + self.cont_names
def n_subsets(self): return 2
def y(self): return self[self.y_names[0]]
def new_empty(self): return self.new(pd.DataFrame({}, columns=self.items.columns))
def to_device(self, d=None):
self.device = d
return self
def all_col_names (self):
ys = [n for n in self.y_names if n in self.items.columns]
return self.x_names + self.y_names if len(ys) == len(self.y_names) else self.x_names
properties(Tabular,'loc','iloc','targ','all_col_names','n_subsets','x_names','y')
# %% ../../nbs/40_tabular.core.ipynb #e23698c9
class TabularPandas(Tabular):
"A `Tabular` object with transforms"
def transform(self, cols, f, all_col=True):
if not all_col: cols = [c for c in cols if c in self.items.columns]
if len(cols) > 0: self[cols] = self[cols].transform(f)
# %% ../../nbs/40_tabular.core.ipynb #efdb998b
def _add_prop(cls, nm):
@property
def f(o): return o[list(getattr(o,nm+'_names'))]
@f.setter
def fset(o, v): o[getattr(o,nm+'_names')] = v
setattr(cls, nm+'s', f)
setattr(cls, nm+'s', fset)
_add_prop(Tabular, 'cat')
_add_prop(Tabular, 'cont')
_add_prop(Tabular, 'y')
_add_prop(Tabular, 'x')
_add_prop(Tabular, 'all_col')
# %% ../../nbs/40_tabular.core.ipynb #5c7cd5ef
class TabularProc(InplaceTransform):
"Base class to write a non-lazy tabular processor for dataframes"
def setup(self, items=None, train_setup=False): #TODO: properly deal with train_setup
super().setup(getattr(items,'train',items), train_setup=False)
# Procs are called as soon as data is available
return self(items.items if isinstance(items,Datasets) else items)
@property
def name(self): return f"{super().name} -- {getattr(self,'__stored_args__',{})}"
# %% ../../nbs/40_tabular.core.ipynb #87389d74
def _apply_cats (voc, add, c):
if not (hasattr(c, 'dtype') and isinstance(c.dtype, CategoricalDtype)):
return pd.Categorical(c, categories=voc[c.name][add:]).codes+add
return c.cat.codes+add #if is_categorical_dtype(c) else c.map(voc[c.name].o2i)
def _decode_cats(voc, c): return c.map(dict(enumerate(voc[c.name].items)))
# %% ../../nbs/40_tabular.core.ipynb #958b9760
class Categorify(TabularProc):
"Transform the categorical variables to something similar to `pd.Categorical`"
order = 1
def setups(self, to):
store_attr(classes={n:CategoryMap(to.iloc[:,n].items, add_na=(n in to.cat_names)) for n in to.cat_names}, but='to')
def encodes(self, to): to.transform(to.cat_names, partial(_apply_cats, self.classes, 1))
def decodes(self, to): to.transform(to.cat_names, partial(_decode_cats, self.classes))
def __getitem__(self,k): return self.classes[k]
# %% ../../nbs/40_tabular.core.ipynb #1a858dde
@Categorize
def setups(self, to:Tabular):
if len(to.y_names) > 0:
if self.vocab is None:
self.vocab = CategoryMap(getattr(to, 'train', to).iloc[:,to.y_names[0]].items, strict=True)
else:
self.vocab = CategoryMap(self.vocab, sort=False, add_na=self.add_na)
self.c = len(self.vocab)
return self(to)
@Categorize
def encodes(self, to:Tabular):
to.transform(to.y_names, partial(_apply_cats, {n: self.vocab for n in to.y_names}, 0), all_col=False)
return to
@Categorize
def decodes(self, to:Tabular):
to.transform(to.y_names, partial(_decode_cats, {n: self.vocab for n in to.y_names}), all_col=False)
return to
# %% ../../nbs/40_tabular.core.ipynb #c786be37
@Normalize
def setups(self, to:Tabular):
store_attr(but='to', means=dict(getattr(to, 'train', to).conts.mean()),
stds=dict(getattr(to, 'train', to).conts.std(ddof=0)+1e-7))
return self(to)
@Normalize
def encodes(self, to:Tabular):
to.conts = (to.conts-self.means) / self.stds
return to
@Normalize
def decodes(self, to:Tabular):
to.conts = (to.conts*self.stds ) + self.means
return to
# %% ../../nbs/40_tabular.core.ipynb #76a90230
class FillStrategy:
"Namespace containing the various filling strategies."
def median (c,fill): return c.median()
def constant(c,fill): return fill
def mode (c,fill): return c.dropna().value_counts().idxmax()
# %% ../../nbs/40_tabular.core.ipynb #e67b4128
class FillMissing(TabularProc):
"Fill the missing values in continuous columns."
def __init__(self, fill_strategy=FillStrategy.median, add_col=True, fill_vals=None):
if fill_vals is None: fill_vals = defaultdict(int)
store_attr()
def setups(self, to):
missing = pd.isnull(to.conts).any()
store_attr(but='to', na_dict={n:self.fill_strategy(to[n], self.fill_vals[n])
for n in missing[missing].keys()})
self.fill_strategy = self.fill_strategy.__name__
def encodes(self, to):
missing = pd.isnull(to.conts)
for n in missing.any()[missing.any()].keys():
assert n in self.na_dict, f"nan values in `{n}` but not in setup training set"
for n in self.na_dict.keys():
to[n] = to[n].fillna(self.na_dict[n])
if self.add_col:
to.loc[:,n+'_na'] = missing[n]
if n+'_na' not in to.cat_names: to.cat_names.append(n+'_na')
# %% ../../nbs/40_tabular.core.ipynb #9be310e6
def _maybe_expand(o): return o[:,None] if o.ndim==1 else o
# %% ../../nbs/40_tabular.core.ipynb #774acf79
class ReadTabBatch(ItemTransform):
"Transform `TabularPandas` values into a `Tensor` with the ability to decode"
def __init__(self, to): self.to = to.new_empty()
def encodes(self, to):
if not to.with_cont: res = (tensor(to.cats).long(),)
else: res = (tensor(to.cats).long(),tensor(to.conts).float())
ys = [n for n in to.y_names if n in to.items.columns]
if len(ys) == len(to.y_names): res = res + (tensor(to.targ),)
if to.device is not None: res = to_device(res, to.device)
return res
def decodes(self, o):
o = [_maybe_expand(o_) for o_ in to_np(o) if o_.size != 0]
vals = np.concatenate(o, axis=1)
try: df = pd.DataFrame(vals, columns=self.to.all_col_names)
except: df = pd.DataFrame(vals, columns=self.to.x_names)
to = self.to.new(df)
return to
# %% ../../nbs/40_tabular.core.ipynb #063a6e8e
@dispatch
def show_batch(x: Tabular, y, its, max_n=10, ctxs=None):
x.show()
# %% ../../nbs/40_tabular.core.ipynb #bcf9ce05
@delegates()
class TabDataLoader(TfmdDL):
"A transformed `DataLoader` for Tabular data"
def __init__(self, dataset, bs=16, shuffle=False, after_batch=None, num_workers=0, **kwargs):
if after_batch is None: after_batch = L(TransformBlock().batch_tfms)+ReadTabBatch(dataset)
super().__init__(dataset, bs=bs, shuffle=shuffle, after_batch=after_batch, num_workers=num_workers, **kwargs)
def create_item(self, s): return self.dataset.iloc[s or 0]
def create_batch(self, b): return self.dataset.iloc[b]
def do_item(self, s): return 0 if s is None else s
TabularPandas._dl_type = TabDataLoader
# %% ../../nbs/40_tabular.core.ipynb #253b8d64
@delegates()
class TabWeightedDL(TabDataLoader):
"A transformed `DataLoader` for Tabular Weighted data"
def __init__(self, dataset, bs=16, wgts=None, shuffle=False, after_batch=None, num_workers=0, **kwargs):
wgts = np.array([1.]*len(dataset) if wgts is None else wgts)
self.wgts = wgts / wgts.sum()
super().__init__(dataset, bs=bs, shuffle=shuffle, after_batch=after_batch, num_workers=num_workers, **kwargs)
self.idxs = self.get_idxs()
def get_idxs(self):
if self.n == 0: return []
if not self.shuffle: return super().get_idxs()
return list(np.random.choice(self.n, self.n, p=self.wgts))
TabularPandas._dl_type = TabWeightedDL
# %% ../../nbs/40_tabular.core.ipynb #67f710b2
@EncodedMultiCategorize
def setups(self, to:Tabular):
self.c = len(self.vocab)
return self(to)
@EncodedMultiCategorize
def encodes(self, to:Tabular): return to
@EncodedMultiCategorize
def decodes(self, to:Tabular):
to.transform(to.y_names, lambda c: c==1)
return to
# %% ../../nbs/40_tabular.core.ipynb #d6b3e995
@RegressionSetup
def setups(self, to:Tabular):
if self.c is not None: return
self.c = len(to.y_names)
return to
@RegressionSetup
def encodes(self, to:Tabular): return to
@RegressionSetup
def decodes(self, to:Tabular): return to