class_docstr: Regression tree for XGBoost
  - Reference -
  http://xgboost.readthedocs.io/en/latest/model.html
class_docstr_tok: ["Regression","tree","for","XGBoost","-","Reference","-","http",":","\/\/xgboost.readthedocs.io\/en\/latest\/model.html"]
docstr: y contains y_true in left half of the middle column and
  y_pred in the right half. Split and return the two matrices 
docstr_tok: ["y","contains","y_true","in","left","half","of","the","middle","column","and","y_pred","in","the","right","half",".","Split","and","return","the","two","matrices"]
code: def _split(self, y):
      """y contains y_true in left half of the middle column and
      y_pred in the right half. Split and return the two matrices"""
      col = int(np.shape(y)[1] / 2)
      y, y_pred = y[:, :col], y[:, col:]
      return y, y_pred
  
imports: from __future__ import division, print_function
  import numpy
  from mlfromscratch.utils import divide_on_feature, train_test_split, standardize, mean_squared_error
  from mlfromscratch.utils import calculate_entropy, accuracy_score, calculate_variance
label_desc: Use image node_id 1 for calling the XGBoostRegressionTree obj's underlying member method code with example usage: obj._split(y) and returns: y,  y_pred