Forum Discussion
Select columns with specified data type
- 4 years ago
Hi,
If you want to select columns using columns' defined type then you could use code like this:
let Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WSkxMVNJRMgRiAz0waa5vYKZvZGBkpBSrA5M2AksbQaXNodKxAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [text = _t, int = _t, decimal = _t, date = _t]), ChangedType = Table.TransformColumnTypes(Source,{{"date", type date}, {"decimal", type number}, {"int", Int64.Type}, {"text", type text}}, "en-US"), TableSchemaCall = Table.Schema(ChangedType), FilteredRows = Table.SelectRows(TableSchemaCall, each ([TypeName] = "Number.Type")), ToList = FilteredRows[Name], SelectionOfColumns = Table.SelectColumns( #"ChangedType",ToList) in SelectionOfColumnsArtur
- 4 years ago
If you see my code, second argument was {type nullable number} and you had put {type number}. Unless you use nullable keyword, it will not give you the result.
If you need name of the columns only, then
= Table.ColumnsOfType(#"Filtered Rows",{type number}) - 4 years ago
If you would like to only select the columns with the type of percentage you can't use Table.ColumsOfType function because it treats all number kinds (whole numbers, decimals, percentage, currency) as numbers. IF for example if you want to select only currencies, you would have to Table.ScemaFunction.
Artur
Table.ColumnsOfType is used for this purpose. Use following to select the columns where #"Changed Type" is previous step
= Table.SelectColumns(#"Changed Type",Table.ColumnsOfType(#"Changed Type", {type nullable number}))
- artpil4 years ago
Resolver II
Ho Vijay_A_Verma,
With this method you can't select only Int64.Type or only Number.Type or only Percentage.Type or only Currency.Type. Am I right?
Artur
- Vijay_A_Verma4 years ago
Most Valuable Professional
You are right.
This method would work only for primitive data types. Primitive data type "number" here would mean following
- Whole number (i.e. Integer)
- Decimal number
- Currency
- Percent
Hence, if you use Percentage.Type, Int64.Type, Number.Type, Currency.Type then the result would be same as that of type number.
Hence, using Int64.Type here woudn't retrieve only Whole number columns but all columns of type number.
Hence, if strictly any particular type is needed, your method is something which a person should go for.
- monojchakrab4 years ago
Resolver III
Hey Vijay_A_Verma ,
I tried this method and I got the following as a result :
There are two problems with this :
1. It has selected all columns irrespective of the type; here's the code I used :
= Table.SelectColumns(#"Filtered Rows",Table.ColumnsOfType(#"Filtered Rows",{type number}))2. It is not giving me the names of the columns - I would need to isolate the names of the columns which are of numeric data type
But appreciate the help
Best regds.,
- Vijay_A_Verma4 years ago
Most Valuable Professional
If you see my code, second argument was {type nullable number} and you had put {type number}. Unless you use nullable keyword, it will not give you the result.
If you need name of the columns only, then
= Table.ColumnsOfType(#"Filtered Rows",{type number})- monojchakrab4 years ago
Resolver III
Thanks Vijay_A_Verma ...the code now works and returns the table only with numeric data types.
But when I tried the code for only column names with numeric data type as below :
Table.ColumnsOfType(#"Filtered Rows",{type number})It is returning just an empty list with nothing in it :
Would really appreciate any help with this one - this will really help in the subsequent processes with this file.
Thanks and appreciate