Augment pandas data frames with methods for machine learning
Project description
pandas-ml-utils
A note of caution: this is a one man show hobby project in pre-alpha state mainly serving my own needs. Be my guest and use it or extend it.
I was really sick of converting data frames to numpy arrays back and forth just to try out a simple logistic regression. So I have started a pandas ml utilities library where everything should be reachable from the data frame itself. Check out the following examples to see what I mean by that.
Fitting
Ordinary Binary Classification
import pandas as pd
import pandas_ml_utils as pmu
from sklearn.datasets import load_breast_cancer
from sklearn.linear_model import LogisticRegression
bc = load_breast_cancer()
df = pd.DataFrame(bc.data, columns = bc.feature_names)
df["label"] = bc.target
fit = df.fit_classifier(pmu.SkitModel(LogisticRegression(solver='lbfgs', max_iter=300),
pmu.FeaturesAndLabels(features=['mean radius', 'mean texture', 'mean perimeter', 'mean area',
'worst concave points', 'worst fractal dimension'],
labels=['label'])),
test_size=0.4)
As a result you get a Fit object which holds the fitted model and two ClassificationSummary. One for the training data and one for the test Data. In case of the classification was executed in a notebook you get a nice table:
Binary Classification with Loss
As you can see in the above example are two confusion matrices the regular well known one and a "loss". The intend of loss matrix is to tell you if a miss classification has a cost i.e. a loss in dollars.
import pandas as pd
import pandas_ml_utils as pmu
from sklearn.linear_model import LogisticRegression
df = pd.fetch_yahoo(spy='SPY')
df["label"] = df["spy_Close"] > df["spy_Open"]
df["loss"] = (df["spy_Open"] / df["spy_Close"] - 1) * 100
fit = df.fit_classifier(pmu.SkitModel(LogisticRegression(solver='lbfgs'),
pmu.FeaturesAndLabels(features=['spy_Open', 'spy_Low'],
labels=['label'],
loss_column='loss')),
test_size=0.4)
Now you can see the loss in % of dollars of your miss classification. The classification probabilities are plotted on the very top of the plot.
Autoregressive Models and RNN Shape
It is also possible to use the FeaturesAndLabels object to generate autoregressive
features. By default lagging features results in an RNN shaped 3D array (in the format
as Keras likes it). However we can also use SkitModels the features will be implicitly
transformed back into a 2D array (by using the reshape_rnn_as_ar
function).
import pandas_ml_utils as pmu
pmu.FeaturesAndLabels(features=['feature'],
labels=['label'],
feature_lags=range(0, 10))
One may like to use very long lags i.e. to catch seasonal effects. Since very long lags are a bit fuzzy I usually like to smooth them a bit by using simple averages.
import pandas_ml_utils as pmu
pmu.FeaturesAndLabels(features=['feature'],
labels=['label'],
target_columns=['strike'],
loss_column='put_loss',
feature_lags=[0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233],
lag_smoothing={
6: lambda df: df.SMA(3, price=df.columns[0]),
35: lambda df: df.SMA(5, price=df.columns[0])
})
Every lag from 6 onwards will be smoothed by a 3 period average, every lag from 35 onwards with a 5 periods moving average.
Back-Testing a Model
todo ...
Save, load reuse a Model
To save a model you simply call the save method on the model inside of the fit.
fit.model.save('/tmp/foo.model')
Loading is as simply as calling load on the Model object. You can immediately apply the model on the dataframe to get back the features along with the classification (which is just another data frame).
import pandas as pd
import pandas_ml_utils as pmu
from sklearn.datasets import load_breast_cancer
bc = load_breast_cancer()
df = pd.DataFrame(bc.data, columns = bc.feature_names)
df.classify(pmu.Model.load('/tmp/foo.model')).tail()
NOTE If you have a target level for your binary classifier like all houses cheaper then
50k then you can define this target level to the FeaturesAndLabels object likes so:
FeaturesAndLabels(target_columns=['House Price'])
. This target column is simply fed
through to the classified dataframe as target columns.
Other utility objects
LazyDataFrame
Very often I need to do a lot of feature engineering. And very often I do not want to treat averages or other engineering methods as part of the data(frame). For this use case I have added a LazyDataFrame object wrapping around a regular DataFrame where some columns will always be calculated on the fly.
Here is an example:
import pandas_ml_utils as pmu
import pandas as pd
import talib
df = pd.fetch_yahoo(spy='SPY')
ldf = pmu.LazyDataFrame(df,
rolling_stddev=lambda x: talib.STDDEV(x['spy_Close'], timeperiod=30) / 100)
ldf["rolling_stddev"].tail() # Will always be calculated only the fly
HashableDataFrame
The hashable dataframe is nothing which should be used directly. However this is just a hack to allow caching of feature matrices. With heavy usage of LazyDataFrame and heavily lagging of features for AR models the training data preparation might take a long time. To shorten this time i.e. for hyper parameter tuning a cache is very helpful (but keep in mind this is still kind of a hack).
to set the cache size (default is 1) set the following environment variable before import
os.environ["CACHE_FEATUES_AND_LABELS"] = "2"
. And to use the cache simply pass the
argument to the fit_classifier method like so:df.fit_classifier(..., cache_feature_matrix=True)
MultiModel
TODO describe multi models ...
TODO
- multi model is just another implementation of model
- provide better and more flexible option to do k folds or any other "optimization" on training data like ove-weighting certain events
- add keras model
- add more tests
Wanna help?
- currently I only need binary classification
- maybe you want to add a feature for multiple classes
- or you want to add non classification prediction models
- write some tests
- add different more charts for a better understanding/interpretation of the models
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