CAPÍTULO IV. RESULTADOS
5.2 R ECOMENDACIONES
8.26.1 Declare Missing Value
Synopsis
Declares a missing numeric or nominal value on a selected subset, which will be replaced by NULL.
Description
The given value will be replaced with NULL throughout the specified subset, so it will be treated as a missing value by subsequent operators.
Input:
• example set input:
– expects: HadoopExampleSet Output:
• example set output
• original Parameters:
• attribute filter type: The condition specifies which attributes are selected or affected by this operator.
– Default value: all
• attribute: The attribute which should be chosen.
– Depends on: attribute filter type = single
• attributes: The attribute which should be chosen.
– Depends on: attribute filter type = subset
• regular expression: A regular expression for the names of the attributes which should be kept.
– Depends on: attribute filter type = regular_expression
• use except expression (expert): If enabled, an exception to the specified regular expression might be specified.
Attributes of matching this will be filtered out, although matching the first expression.
– Default value: false
– Depends on: attribute filter type = regular_expression
• except regular expression (expert): A regular expression for the names of the attributes which should be filtered out although matching the above regular expression.
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– Depends on: use except expression = true, attribute filter type = regular_expression
• value type: The value type of the attributes.
– Default value: attribute_value
– Depends on: attribute filter type = value_type
• use value type exception (expert): If enabled, an exception to the specified value type might be specified. At-tributes of this type will be filtered out, although matching the first specified type.
– Default value: false
– Depends on: attribute filter type = value_type
• except value type (expert): Except this value type.
– Default value: time
– Depends on: use value type exception = true, attribute filter type = value_type
• block type: The block type of the attributes.
– Default value: attribute_block
– Depends on: attribute filter type = block_type
• use block type exception (expert): If enabled, an exception to the specified block type might be specified.
– Default value: false
– Depends on: attribute filter type = block_type
• except block type (expert): Except this block type.
– Default value: value_matrix_row_start
– Depends on: use block type exception = true, attribute filter type = block_type
• numeric condition: Parameter string for the condition, e.g. ‘>= 5’
– Depends on: attribute filter type = numeric_value_filter
• invert selection: Indicates if only attributes should be accepted which would normally filtered.
– Default value: false
• include special attributes: Indicate if this operator should also be applied on the special attributes. Otherwise they are always kept.
– Default value: false
• attribute value: This parameter defines the missing value
8.26.2 Normalize
Synopsis
Normalizes the attribute values for a specified range.
Description
This operator performs a normalization. This can be done between a user defined minimum and maximum value or by a z-transformation, i.e. on mean 0 and variance 1.
Input:
• example set input:
– expects: HadoopExampleSet Output:
• example set output
• original Parameters:
• attribute filter type: The condition specifies which attributes are selected or affected by this operator.
– Default value: all
• attribute: The attribute which should be chosen.
– Depends on: attribute filter type = single
• attributes: The attribute which should be chosen.
– Depends on: attribute filter type = subset
• regular expression: A regular expression for the names of the attributes which should be kept.
– Depends on: attribute filter type = regular_expression
• use except expression (expert): If enabled, an exception to the specified regular expression might be specified.
Attributes of matching this will be filtered out, although matching the first expression.
– Default value: false
– Depends on: attribute filter type = regular_expression
• except regular expression (expert): A regular expression for the names of the attributes which should be filtered out although matching the above regular expression.
– Depends on: use except expression = true, attribute filter type = regular_expression
• value type: The value type of the attributes.
– Default value: attribute_value
– Depends on: attribute filter type = value_type
• use value type exception (expert): If enabled, an exception to the specified value type might be specified. At-tributes of this type will be filtered out, although matching the first specified type.
– Default value: false
– Depends on: attribute filter type = value_type
• except value type (expert): Except this value type.
– Default value: time
– Depends on: use value type exception = true, attribute filter type = value_type
• block type: The block type of the attributes.
– Default value: attribute_block
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– Depends on: attribute filter type = block_type
• use block type exception (expert): If enabled, an exception to the specified block type might be specified.
– Default value: false
– Depends on: attribute filter type = block_type
• except block type (expert): Except this block type.
– Default value: value_matrix_row_start
– Depends on: use block type exception = true, attribute filter type = block_type
• numeric condition: Parameter string for the condition, e.g. ‘>= 5’
– Depends on: attribute filter type = numeric_value_filter
• invert selection: Indicates if only attributes should be accepted which would normally filtered.
– Default value: false
• include special attributes: Indicate if this operator should also be applied on the special attributes. Otherwise they are always kept.
– Default value: false
• normalize method (expert): Transformation method – Default value: Z-transformation
• min value (expert): Min value – Default value: 0.0
– Depends on: normalize method = Range transformation
• max value (expert): Max value – Default value: 1.0
– Depends on: normalize method = Range transformation
8.26.3 Replace
Synopsis
This operator replaces parts of the values of nominal attributes.
Description
This operator replaces parts of the string values of all nominal attributes it is applied on. The attribute filter type gives the possibility to restrict them. For each value of each attribute it is checked if the regular expression of replace what matches the string. Each matching part of the string will be replaced by the value of the replace_what parameter. The replacement might be empty and can contain capturing groups.
Please keep in mind that although regular expressions are much more powerful than simple strings, you might simply enter characters to search for.
Examples
The attribute contains the values “color red”, “color green” and “color blue”.
• replacing “color” by “” yields: ” red”, ” green”, ” blue”
• replacing “color” by “colour” yields: “colour red”, “colour green”, “colour blue”
• replacing “color\s” by “” yields: “red”, “green”, “blue”
• replacing “\s+” by “_” yields: “color_red”, “color_green”, “color_blue”
• replacing “color\s(.*)” by “$1” yields: “red”, “green”, “blue”
• replacing ”.*\s(.*)” by “$1” yields: “red”, “green”, “blue”
Input:
• example set input:
– expects: HadoopExampleSet Output:
• example set output
• original Parameters:
• attribute filter type: The condition specifies which attributes are selected or affected by this operator.
– Default value: all
• attribute: The attribute which should be chosen.
– Depends on: attribute filter type = single
• attributes: The attribute which should be chosen.
– Depends on: attribute filter type = subset
• regular expression: A regular expression for the names of the attributes which should be kept.
– Depends on: attribute filter type = regular_expression
• use except expression (expert): If enabled, an exception to the specified regular expression might be specified.
Attributes of matching this will be filtered out, although matching the first expression.
– Default value: false
– Depends on: attribute filter type = regular_expression
• except regular expression (expert): A regular expression for the names of the attributes which should be filtered out although matching the above regular expression.
– Depends on: use except expression = true, attribute filter type = regular_expression
• value type: The value type of the attributes.
– Default value: nominal
– Depends on: attribute filter type = value_type
• use value type exception (expert): If enabled, an exception to the specified value type might be specified. At-tributes of this type will be filtered out, although matching the first specified type.
– Default value: false
– Depends on: attribute filter type = value_type
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• except value type (expert): Except this value type.
– Default value: file_path
– Depends on: use value type exception = true, attribute filter type = value_type
• block type: The block type of the attributes.
– Default value: single_value
– Depends on: attribute filter type = block_type
• use block type exception (expert): If enabled, an exception to the specified block type might be specified.
– Default value: false
– Depends on: attribute filter type = block_type
• except block type (expert): Except this block type.
– Default value: single_value
– Depends on: use block type exception = true, attribute filter type = block_type
• numeric condition: Parameter string for the condition, e.g. ‘>= 5’
– Depends on: attribute filter type = numeric_value_filter
• invert selection: Indicates if only attributes should be accepted which would normally filtered.
– Default value: false
• include special attributes: Indicate if this operator should also be applied on the special attributes. Otherwise they are always kept.
– Default value: false
• replace what: A regular expression specifying what should be replaced.
• replace by: The replacement for the region matched by the regular expression. Possibly including capturing groups.