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- sign(column_expression_or_constant)
- DESCRIPTION:
Function returns the sign of a numeric argument.
SIGN functions as follows:
* If numeric value is < 0, -1 is returned.
* If numeric value is = 0, 0 is returned.
* If numeric value is > 0, 1 is returned.
PARAMETERS:
column_expression_or_constant:
Required Argument.
Specifies a ColumnExpression of a numeric column or a constant value.
Format for the argument: '<dataframe>.<dataframe_column>.expression'.
NOTE:
Function accepts positional arguments only.
EXAMPLES:
# Load the data to run the example.
>>> load_example_data("dataframe", "admissions_train")
>>>
# Create a DataFrame on 'admissions_train' table.
>>> admissions_train = DataFrame("admissions_train")
>>> admissions_train
masters gpa stats programming admitted
id
22 yes 3.46 Novice Beginner 0
36 no 3.00 Advanced Novice 0
15 yes 4.00 Advanced Advanced 1
38 yes 2.65 Advanced Beginner 1
5 no 3.44 Novice Novice 0
17 no 3.83 Advanced Advanced 1
34 yes 3.85 Advanced Beginner 0
13 no 4.00 Advanced Novice 1
26 yes 3.57 Advanced Advanced 1
19 yes 1.98 Advanced Advanced 0
>>>
# Import func from sqlalchemy to execute sign() function.
>>> from sqlalchemy import func
# Create a sqlalchemy Function object and pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(sign_gpa = func.sign(admissions_train.gpa.expression),
... sign_const = func.sign(-3))
>>> print(df)
masters gpa stats programming admitted sign_const sign_gpa
id
5 no 3.44 Novice Novice 0 -1 1
34 yes 3.85 Advanced Beginner 0 -1 1
13 no 4.00 Advanced Novice 1 -1 1
40 yes 3.95 Novice Beginner 0 -1 1
22 yes 3.46 Novice Beginner 0 -1 1
19 yes 1.98 Advanced Advanced 0 -1 1
36 no 3.00 Advanced Novice 0 -1 1
15 yes 4.00 Advanced Advanced 1 -1 1
7 yes 2.33 Novice Novice 1 -1 1
17 no 3.83 Advanced Advanced 1 -1 1
>>>
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