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- instr(source_string, search_string, position, occurrence)
- DESCRIPTION:
Function searches the source_string argument for occurrences of search_string.
PARAMETERS:
source_string:
Required Argument.
Specifies a ColumnExpression of a string column or a string literal.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
search_string:
Required Argument.
Specifies a ColumnExpression of a string column or a string literal
that the function searches for in source_string.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
position:
Optional Argument.
Specifies the position as an integer to begin searching at in the source_string.
If position is not specified, the search starts at the beginning of source_string.
If position is negative, the function counts and searches backwards from the end of
source_string.
It cannot have a value of zero.
occurrence:
Optional Argument.
Specifies an integer which decides occurrence of search_string to find in source_string.
If occurrence is not specified, the function searches for the first occurrence.
If occurrence is greater than 1, the function searches for additional occurrences
beginning with the second character in the previous occurrence.
It cannot be zero or a negative 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 searches for a string "e" in "programming" column values.
# Import func from sqlalchemy to execute instr function.
>>> from sqlalchemy import func
# Create a sqlalchemy Function object.
>>> instr_func_ = func.instr(admissions_train.programming.expression, "e")
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(instr_e_in_programming_=instr_func_)
>>> print(df)
masters gpa stats programming admitted instr_e_in_programming_
id
15 yes 4.00 Advanced Advanced 1 7
7 yes 2.33 Novice Novice 1 6
22 yes 3.46 Novice Beginner 0 2
17 no 3.83 Advanced Advanced 1 7
13 no 4.00 Advanced Novice 1 6
38 yes 2.65 Advanced Beginner 1 2
26 yes 3.57 Advanced Advanced 1 7
5 no 3.44 Novice Novice 0 6
34 yes 3.85 Advanced Beginner 0 2
40 yes 3.95 Novice Beginner 0 2
>>>
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