Replace missing values with group mean

[saddas]

I have a data set that includes the following columns:

Table 1: Date, City, Value.

The Value column has some missing values, and I would like to replace those missing values with the group means of City (e.g., all missing values for Paris will take on the mean value of Paris, etc.). In this sample data set, there are only 3 cities, but I am looking for a scalable solution (e.g., the dataset may have 50 cities). 

What's the easiest way of doing that?

Here is a link to the data set: https://www.dropbox.com/sh/9g6uvptyzazfl0u/AAAsElP-PuQxtnJOHCa-BGLWa?dl=0

Thanks.

[smpa01 · Accepted solution]

@saddas  you mean this

Column = IF('Table 1'[Value]=BLANK(), CALCULATE(AVERAGE('Table 1'[Value]),ALLEXCEPT('Table 1','Table 1'[City])),'Table 1'[Value])

[saddas]

Great, thanks very much.