Converting list elements based on their lengths

[Merleau]

Hello,

One column in my table is a list of strings. I would like to change the strings to lower case if their lenghts is greater than 1.

Name	Types
N1	A,ABC,B,CDF,DF
N2	H,JKL,BG,DC,C

Convert to

Name	Types
N1	A,abc,B,cdf,df
N2	H,jkl,bg,dc,C

Can somebody help?

Thank you

[ThxAlot]

For fun only, to incorporate the power of regex,

import re
import numpy as np
df['Types']=np.vectorize(lambda string:re.compile(r'[a-z]{2,}(?=\b)',flags=re.I).sub(lambda match:str.lower(match.group(0)),string))(df['Types'])

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W8jNUUFBQ0lFy1HF0ctZx0nF2cdNxcVOK1QFKGQHFPXS8vH10nNx1XJx1nJViYwE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Name = _t, Types = _t]),
    #"Run Python script" = Python.Execute("import re#(lf)import numpy as np#(lf)df['Types']=np.vectorize(lambda string:re.compile(r'[a-z]{2,}(?=\b)',flags=re.I).sub(lambda match:str.lower(match.group(0)),string))(df['Types'])",[df=Source]),
    df = #"Run Python script"{[Name="df"]}[Value]
in
    df

[AlienSx]

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W8jNUUFBQ0lFy1HF0ctZx0nF2cdNxcVOK1QFKGQHFPXS8vH10nNx1XJx1nJViYwE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Name      " = _t, Types = _t]),
    chars = List.Buffer({"a".."z", "A".."Z"}), 
    result = Table.TransformColumns(
        Source, 
        {
            "Types", 
            (x) => Text.Combine(
                List.Transform(
                    Text.Split(x, ","), 
                    (w) => if List.Contains(chars, w) then w else Text.Lower(w)
                ),
                ","
            )
        }
    )
in
    result

[jgeddes · Accepted solution]

Here is one way to do this...

= Table.TransformColumns(previousQueryStep, {{"Types", each Text.Combine(List.Transform(Text.Split(_, ","), each if Text.Length(_) > 1 then Text.Lower(_) else _), ","), type text}})

Using your example table you end up with...

[Merleau]

Thank you @jgeddes 

This is perfect!