Python list of lists remove single quotes on one value-CodePudding

I have a list of fields an am trying to create an unpivot expression with stack() in pyspark.

stack() requires the params: number, field name, then field value. stack(30, 'field1', field1...)

I have a list of lists like

[['field1','field1'],['field2','field2']...]

I then can make a single list

['field1','field1','field2','field2']

But i need to remove the single quotes from the second occurence, so it works as the "field value"

unpivot_Expr = "stack(30, 'field1',field1,'field2',field2...)"

So far i'm getting stack(30, 'field1','field1','field2','field2'...) I'm not sure how, or which is the easiest place to remove the single quotes? Any help is much appreciated.

Edit: Sorry should've given context, I need to insert this string into a pyspark select expression

unpivot_df = df.select("hashKey", expr(unpivot_Expr))

Currently I drop the list into the string and replace the [] like this

unpivot_Expr = "stack({0}, {1})".format(str(len(fieldList)), str(fieldList).replace("[","").replace("]",""))

CodePudding user response：

How about building up the string unpivot_Expr piece by piece via:

all_fields = [
    ['field1','field1'],
    ['field2','field2']
]

unpivot_Expr = "stack(30"
for pair in all_fields:
    unpivot_Expr   = f", '{pair[0]}', {pair[1]}"
unpivot_Expr  = ")"

print(unpivot_Expr)

I think that will give you the tring you seek:

stack(30, 'field1', field1, 'field2', field2)