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- locate(string_expr1, string_expr2, n1)
- DESCRIPTION:
Function returns the position of the first occurrence of string_expr1 within string_expr2.
The search for the first occurrence of string_expr1 begins with the first character
position in string_expr2 unless the optional argument, n1, is specified.
PARAMETERS:
string_expr1:
Required Argument.
Specifies a ColumnExpression of a string column or a string literal for
substring to be searched for its position within the full string.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
Support types of arguments:
1. Character, except for CLOB
2. Byte, except for BLOB
If string_expr1 is of type BYTE, then string_expr2 must be of type BYTE.
3. Numeric - This is converted implicitly to CHARACTER type.
string_expr2:
Required Argument.
Specifies a ColumnExpression of a string column or a string literal for
the full string to be searched in "string_expr1".
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
Support types of arguments:
1. Character, except for CLOB
2. Byte, except for BLOB
If string_expr1 is of type BYTE, then string_expr2 must be of type BYTE.
3. Numeric - This is converted implicitly to CHARACTER type.
n1:
Optional Argument.
Specifies where the search begins with the character position indicated by the
value of n1. Accepts a positive integer value.
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 returns the position of "ce" in a string in "stats" column.
# Import func from sqlalchemy to execute locate function.
>>> from sqlalchemy import func
# Create a sqlalchemy Function object.
>>> locate_func_ = func.locate("ce", admissions_train.stats.expression)
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(locate_stats_=locate_func_)
>>> print(df)
masters gpa stats programming admitted locate_stats_
id
5 no 3.44 Novice Novice 0 5
34 yes 3.85 Advanced Beginner 0 6
13 no 4.00 Advanced Novice 1 6
40 yes 3.95 Novice Beginner 0 5
22 yes 3.46 Novice Beginner 0 5
19 yes 1.98 Advanced Advanced 0 6
36 no 3.00 Advanced Novice 0 6
15 yes 4.00 Advanced Advanced 1 6
7 yes 2.33 Novice Novice 1 5
17 no 3.83 Advanced Advanced 1 6
>>>
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