Problem
You want to measure the numeric (minimum, maximum, sum, average) or textual (characters, words, lines) features of a list of objects.
Solution
Use the MeasureObject cmdlet to measure these statistical properties of a list. To measure the numeric features of a stream of objects, pipe those objects to the MeasureObject cmdlet: PS >1..10 | MeasureObject –Average Sum
Count : 10 Average : 5.5 Sum : 55 Maximum : Minimum : Property :
To measure the numeric features of a specific property in a stream of objects, supply that property name to the –Property parameter of the MeasureObject cmdlet. For example, in a directory with files:
PS >GetChildItem | MeasureObject Property Length Max Min Average Sum
Count : 427 Average : 10617025.4918033 Sum : 4533469885 Maximum : 647129088 Minimum : 0 Property : Length
To measure the textual features of a stream of objects, use the –Character, Word, and –Line parameters of the MeasureObject cmdlet:
PS >GetChildItem > output.txt PS >GetContent output.txt | MeasureObject Character Word Line
Lines
Words
Characters Property
964
6083
33484
Discussion
By default, the MeasureObject cmdlet counts only the number of objects it receives. If you want to measure additional properties (such as the maximum, minimum, average, sum, characters, words, or lines) of those objects, then you need to specify them as options to the cmdlet.
For the numeric properties, though, you usually don’t want to measure the objects themselves. Instead, you probably want to measure a specific property from the list—such as the Length property of a file. For that purpose, the MeasureObject cmdlet supports the –Property parameter to which you provide the property you want to measure.
Sometimes, you might want to measure a property that isn’t a simple number—such as the LastWriteTime property of a file. Since the LastWriteTime property is a DateTime, you can’t determine its average immediately. However, if any property allows you to convert it to a number and back in a meaningful way (such as the Ticks property of a DateTime), then you can still compute its statistical properties. Example 62 shows how to get the average LastWriteTime from a list of files.
Example 62. Using the Ticks property of the DateTime class to determine the average LastWriteTime of a list of files
PS >## Get the LastWriteTime from each file PS >$times = dir | ForeachObject { $_.LastWriteTime }
PS >## Measure the average Ticks property of those LastWriteTime
Example 62. Using the Ticks property of the DateTime class to determine the average LastWriteTime of a list of files (continued)
PS >$results = $times | MeasureObject Ticks Average
PS >## Create a new DateTime out of the average Ticks PS >NewObject DateTime $results.Average
Sunday, June 11, 2006 6:45:01 AM
For more information about the MeasureObject cmdlet, type GetHelp MeasureObject.
