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- ltrim(expression1, expression2)
- DESCRIPTION:
Function returns the argument expression1, with its left-most characters removed up
to the first character that is not in the argument expression2.
PARAMETERS:
expression1:
Required Argument.
Specifies a ColumnExpression of a string column or a string literal.
If argument is NULL, NULL is returned.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
expression2:
Optional Argument.
Specifies a ColumnExpression of a string column or a string literal that
will be removed from string in expression1. If expression2 is specified, it must
be the same data type as expression1. If expression2 is not specified, the default is
to use a single space character.
Format of a ColumnExpression of a string column: '<dataframe>.<dataframe_column>.expression'.
Note:
Column expression of both arguments can be of following type:
a. Character/String types: CHAR, VARCHAR, or CLOB
b. Integer types: BYTEINT, SMALLINT, INTEGER, or BIGINT
c. Numeric types: FLOAT, REAL, DOUBLE PRECISION, DECIMAL, NUMERIC, or NUMBER
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 left trim string in "stats" column if it has "Adv"
# Import func from sqlalchemy to execute ltrim function.
>>> from sqlalchemy import func
# Create a sqlalchemy Function object.
>>> ltrim_func_ = func.ltrim(admissions_train.stats.expression, "Adv")
>>>
# Pass the Function object as input to DataFrame.assign().
>>> df = admissions_train.assign(ltrim_gpa_=ltrim_func_)
>>> print(df)
masters gpa stats programming admitted ltrim_gpa_
id
15 yes 4.00 Advanced Advanced 1 anced
7 yes 2.33 Novice Novice 1 Novice
22 yes 3.46 Novice Beginner 0 Novice
17 no 3.83 Advanced Advanced 1 anced
13 no 4.00 Advanced Novice 1 anced
38 yes 2.65 Advanced Beginner 1 anced
26 yes 3.57 Advanced Advanced 1 anced
5 no 3.44 Novice Novice 0 Novice
34 yes 3.85 Advanced Beginner 0 anced
40 yes 3.95 Novice Beginner 0 Novice
>>>
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