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- concat(column_expression1, column_expression2, column_expression_n)
- DESCRIPTION:
Function returns a string formed by concatenating the arguments in a
left-to-right direction.
PARAMETERS:
column_expression1:
Required Argument.
Specifies a ColumnExpression of a byte, numeric, or string column or a literal.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
column_expression2:
Required Argument.
Specifies a ColumnExpression of a byte, numeric, or string column or a literal.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
column_expression_n:
Optional Arguments.
Specifies multiple ColumnExpressions of a byte, numeric, or string column or literal
that can be used for concatenation.
Format of a ColumnExpression of a string column: '<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 concat function.
>>> from sqlalchemy import func
# Example 1: Concatenate strings from "stats" and "programming" columns.
# Create a sqlalchemy Function object.
>>> concat_func_ = func.concat(admissions_train.stats.expression, admissions_train.programming.expression)
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(concat_gpa_=concat_func_)
>>> print(df)
masters gpa stats programming admitted concat_gpa_
id
15 yes 4.00 Advanced Advanced 1 AdvancedAdvanced
7 yes 2.33 Novice Novice 1 NoviceNovice
22 yes 3.46 Novice Beginner 0 NoviceBeginner
17 no 3.83 Advanced Advanced 1 AdvancedAdvanced
13 no 4.00 Advanced Novice 1 AdvancedNovice
38 yes 2.65 Advanced Beginner 1 AdvancedBeginner
26 yes 3.57 Advanced Advanced 1 AdvancedAdvanced
5 no 3.44 Novice Novice 0 NoviceNovice
34 yes 3.85 Advanced Beginner 0 AdvancedBeginner
40 yes 3.95 Novice Beginner 0 NoviceBeginner
>>>
# Example 2: Concatenate strings from "programming" columns and numeric value from "gpa" column
# with sevaral literal values.
# Create a sqlalchemy Function object.
>>> concat_func_ = func.concat("Student with id: ", admissions_train.id.expression, " has gpa: ", admissions_train.gpa.expression, " and '", admissions_train.programming.expression, "' programming skills.")
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(concat_string_=concat_func_)
>>> df = admissions_train.assign(concat_string_=concat_func_)
>>> print(df)
masters gpa stats programming admitted concat_string_
id
22 yes 3.46 Novice Beginner 0 Student with id: 22 has gpa: 3.46000000000000E 000 and 'Beginner' programming skills.
26 yes 3.57 Advanced Advanced 1 Student with id: 26 has gpa: 3.57000000000000E 000 and 'Advanced' programming skills.
5 no 3.44 Novice Novice 0 Student with id: 5 has gpa: 3.44000000000000E 000 and 'Novice' programming skills.
17 no 3.83 Advanced Advanced 1 Student with id: 17 has gpa: 3.83000000000000E 000 and 'Advanced' programming skills.
13 no 4.00 Advanced Novice 1 Student with id: 13 has gpa: 4.00000000000000E 000 and 'Novice' programming skills.
19 yes 1.98 Advanced Advanced 0 Student with id: 19 has gpa: 1.98000000000000E 000 and 'Advanced' programming skills.
36 no 3.00 Advanced Novice 0 Student with id: 36 has gpa: 3.00000000000000E 000 and 'Novice' programming skills.
15 yes 4.00 Advanced Advanced 1 Student with id: 15 has gpa: 4.00000000000000E 000 and 'Advanced' programming skills.
34 yes 3.85 Advanced Beginner 0 Student with id: 34 has gpa: 3.85000000000000E 000 and 'Beginner' programming skills.
38 yes 2.65 Advanced Beginner 1 Student with id: 38 has gpa: 2.65000000000000E 000 and 'Beginner' programming skills.
>>>
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