Using if else statement inside functools.reduce

Question

i have created a function which is working fine, however, i would like to add if else statement inside function.reduce and im not sure if this is achievable. tried researching on func.reduce but there wasnt any information / use-case available on how i want to function to work. would need some advice if this is possible in python or should i go on another approach.

I have created this function which is working as expected, '

def tempJoin(df,targetField,targetTitle,condition,targetResult,otherwise,show=False,lowercase=False):
    case_conditions = list(zip(condition, targetResult))
    product_col = functools.reduce(
        lambda acc, x: acc.when(col(targetField).like(x[0]), F.lit(x[1])),case_conditions,F,).otherwise(otherwise)
    df = df.withColumn(targetTitle, product_col)

    if show:
        df.show(10)
        
    return df;

i am fully aware that i could go with this approach, but i feel this can be further optimise

def tempJoin(df,targetField,targetTitle,condition,targetResult,otherwise,show=False,lowercase=False):
    case_conditions = list(zip(condition, targetResult))
    if lowercase :
        product_col = functools.reduce(
            lambda acc, x: acc.when(lower(col(targetField)).like(x[0]), F.lit(x[1])),case_conditions,F,).otherwise(otherwise)        
    else :
        product_col = functools.reduce(
            lambda acc, x: acc.when(col(targetField).like(x[0]), F.lit(x[1])),case_conditions,F,).otherwise(otherwise)
    
    df = df.withColumn(targetTitle, product_col)

    if show:
        df.show(10)
        
    return df;

what i am trying to achieve is to add if else of 'lowercase=True', it will triggers within functools itself. something as this shown below

 product_col = functools.reduce(
            if lowercase:
                lambda acc, x: acc.when(lower(col(targetField)).like(x[0]), F.lit(x[1])),case_conditions,F,).otherwise(otherwise)
            else:
                lambda acc, x: acc.when(col(targetField).like(x[0]), F.lit(x[1])),case_conditions,F,).otherwise(otherwise)

is this achievable?

Answer 1

So you're looking for an "inline" if statement? Python calls those conditional expressions .

The general syntax is some_value if condition else other_value

So your code would be:

product_col = functools.reduce(lambda ... if lowercase else lambda ...)

Answer 2

You can put the ternary expression inside the when clause:

product_col = functools.reduce(
    lambda acc, x:
        acc.when(
            (lower(col(targetField)) if lowercase else col(targetField)).like(x[0]), 
            F.lit(x[1])
        ), case_conditions, F
).otherwise(otherwise)