Page tree



Contents:

The cloud-based version of Trifacta Wrangler is now available! Read all about it, and register for your free account.

This example illustrates how you can use the following conditional calculation functions to analyze weather data:

  • AVERAGEIF - Average of a set of values by group that meet a specified condition. See AVERAGEIF Function.
  • MINIF - Minimum of a set of values by group that meet a specified condition. See MINIF Function.
  • MAXIF - Maximum of a set of values by group that meet a specified condition. See MAXIF Function.
  • VARIF - Variance of a set of values by group that meet a specified condition. See VARIF Function.
  • STDEVIF - Standard deviation of a set of values by group that meet a specified condition. See STDEVIF Function.

Source:

Here is some example weather data:

datecityraintempwind
1/23/17Valleyville0.0012.86.7
1/23/17Center Town0.319.45.3
1/23/17Magic Mountain0.000.07.3
1/24/17Valleyville0.2517.23.3
1/24/17Center Town0.541.17.6
1/24/17Magic Mountain0.325.08.8
1/25/17Valleyville0.023.36.8
1/25/17Center Town0.833.35.1
1/25/17Magic Mountain0.59-1.76.4
1/26/17Valleyville1.0815.04.2
1/26/17Center Town0.966.17.6
1/26/17Magic Mountain0.77-3.93.0
1/27/17Valleyville1.007.22.8
1/27/17Center Town1.3220.00.2
1/27/17Magic Mountain0.775.65.2
1/28/17Valleyville0.12-6.15.1
1/28/17Center Town0.145.04.9
1/28/17Magic Mountain1.501.10.4
1/29/17Valleyville0.3613.37.3
1/29/17Center Town0.756.19.0
1/29/17Magic Mountain0.603.36.0


Transformation:

The following computes average temperature for rainy days by city:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula AVERAGEIF(temp, rain > 0)
Parameter: Group rows by city
Parameter: New column name 'avgTempWRain'

The following computes maximum wind for sub-zero days by city:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula MAXIF(wind,temp < 0)
Parameter: Group rows by city
Parameter: New column name 'maxWindSubZero'

This step calculates the minimum temp when the wind is less than 5 mph by city:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula MINIF(temp,wind<5)
Parameter: Group rows by city
Parameter: New column name 'minTempWind5'

This step computes the variance in temperature for rainy days by city:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula VARIF(temp,rain >0)
Parameter: Group rows by city
Parameter: New column name 'varTempWRain'

The following computes the standard deviation in rainfall for Center Town:

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula STDEVIF(rain,city=='Center Town')
Parameter: Group rows by city
Parameter: New column name 'stDevRainCT'

You can use the following transforms to format the generated output. Note the $col placeholder value for the multi-column transforms:

Transformation Name Edit column with formula
Parameter: Columns stDevRainCenterTown,maxWindSubZero
Parameter: Formula numformat($col,'##.##')

Since the following rely on data that has only one significant digit, you should format them differently:

Transformation Name Edit column with formula
Parameter: Columns varTempWRain,avgTempWRain,minTempWind5
Parameter: Formula numformat($col,'##.#')

Results:

datecityraintempwindavgTempWRainmaxWindSubZerominTempWind5varTempWRainstDevRainCT
1/23/17Valleyville0.0012.86.78.35.17.263.80.37
1/23/17Center Town0.319.45.37.3 532.60.37
1/23/17Magic Mountain0.000.07.31.66.43-3.9120.37
1/24/17Valleyville0.2517.23.38.35.17.263.80.37
1/24/17Center Town0.541.17.67.3 532.60.37
1/24/17Magic Mountain0.325.08.81.66.43-3.9120.37
1/25/17Valleyville0.023.36.88.35.17.263.80.37
1/25/17Center Town0.833.35.17.3 532.60.37
1/25/17Magic Mountain0.59-1.76.41.66.43-3.9120.37
1/26/17Valleyville1.0815.04.28.35.17.263.80.37
1/26/17Center Town0.966.17.67.3 532.60.37
1/26/17Magic Mountain0.77-3.93.01.66.43-3.9120.37
1/27/17Valleyville1.007.22.88.35.17.263.80.37
1/27/17Center Town1.3220.00.27.3 532.60.37
1/27/17Magic Mountain0.775.65.21.66.43-3.9120.37
1/28/17Valleyville0.12-6.15.18.35.17.263.80.37
1/28/17Center Town0.145.04.97.3 532.60.37
1/28/17Magic Mountain1.501.10.41.66.43-3.9120.37
1/29/17Valleyville0.3613.37.38.35.17.263.80.37
1/29/17Center Town0.756.19.07.3 532.60.37
1/29/17Magic Mountain0.603.36.01.66.43-3.9120.37

Your Rating: Results: 1 Star2 Star3 Star4 Star5 Star 11 rates

This page has no comments.