| | |
- atan2(x, y)
- DESCRIPTION:
Function computes the arctangent value based on x and y coordinates provided as inputs.
The arctangent is the angle whose tangent is the argument.
Notes:
1. Result values return an angle between -π and π radians, excluding -π.
2. A positive result represents a counterclockwise angle from the x-axis.
3. A negative result represents a clockwise angle from the x-axis.
4. If both x and y are 0, an error is returned.
PARAMETERS:
x:
Required Argument.
Specifies the x-coordinate of a point to use in the arctangent calculation.
Accepts a ColumnExpression of a numeric column or a numeric constant.
Format for ColumnExpression the argument: '<dataframe>.<dataframe_column>.expression'.
y:
Required Argument.
Specifies the y-coordinate of a point to use in the arctangent calculation.
Accepts a ColumnExpression of a numeric column or a numeric constant.
Format for the argument: '<dataframe>.<dataframe_column>.expression'.
Notes:
1. If the type of the column/argument is not FLOAT, column values are converted to FLOAT
based on implicit type conversion rules. If an argument cannot be converted, an
error is reported.
2. Unsupported column types:
a. BYTE or VARBYTE
b. LOBs (BLOB or CLOB)
c. CHARACTER or VARCHAR if the server character set is GRAPHIC
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
>>>
# Example calculates arctangent value for the "gpa" column values as x-coordinate and
# a numeric value 1 as y-coordinate with help of SQLAlchemy.
# Import func from sqlalchemy to execute atan2() function.
>>> from sqlalchemy import func
# Create a sqlalchemy Function object.
>>> atan2_func_ = func.atan2(admissions_train.gpa.expression, 1)
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(atan2_gpa_=atan2_func_)
>>> print(df)
masters gpa stats programming admitted atan2_gpa_
id
5 no 3.44 Novice Novice 0 0.282901
34 yes 3.85 Advanced Beginner 0 0.254125
13 no 4.00 Advanced Novice 1 0.244979
40 yes 3.95 Novice Beginner 0 0.247955
22 yes 3.46 Novice Beginner 0 0.281351
19 yes 1.98 Advanced Advanced 0 0.467680
36 no 3.00 Advanced Novice 0 0.321751
15 yes 4.00 Advanced Advanced 1 0.244979
7 yes 2.33 Novice Novice 1 0.405410
17 no 3.83 Advanced Advanced 1 0.255395
>>>
|