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- cos(column_expression)
- DESCRIPTION:
Function computes the cosine value of an argument.
The cosine of an angle is the ratio of two sides of a right triangle.
The ratio is the length of the side adjacent to the angle divided by
the length of the hypotenuse.
The cosine of argument returns values in radians in the range -1 to 1, inclusive.
PARAMETERS:
column_expression:
Required Argument.
Specifies a ColumnExpression of a numeric column or a numeric constant
on which cos() is requested.
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 cosine value for the "gpa" column with help of SQLAlchemy.
# Import func from sqlalchemy to execute cos() function.
>>> from sqlalchemy import func
# Create a sqlalchemy Function object.
>>> cos_func_ = func.cos(admissions_train.gpa.expression)
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(cos_gpa_=cos_func_)
>>> print(df)
masters gpa stats programming admitted cos_gpa_
id
15 yes 4.00 Advanced Advanced 1 -0.653644
7 yes 2.33 Novice Novice 1 -0.688344
22 yes 3.46 Novice Beginner 0 -0.949735
17 no 3.83 Advanced Advanced 1 -0.772259
13 no 4.00 Advanced Novice 1 -0.653644
38 yes 2.65 Advanced Beginner 1 -0.881582
26 yes 3.57 Advanced Advanced 1 -0.909629
5 no 3.44 Novice Novice 0 -0.955806
34 yes 3.85 Advanced Beginner 0 -0.759399
40 yes 3.95 Novice Beginner 0 -0.690651
>>>
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