Powershell ForEach 和 ForEach-Object 与 Select

Question

i was trying to loop through a list of file names in $s4a using ForEach and ForEach-Object and display output. The only two ways i found that generate output are:

• ForEach ($name in $s4a) {$name.Name}
• $s4a| ForEach-Object {$_ | Select Name}

Can someone please let me know why the ones below generate nothing, while the above two work?

• ForEach ($name in $s4a) {Select Name} #No result
• ForEach ($name in $s4a) {Select $name.Name} #No result
• $s4a| ForEach-Object {Select$_.Name} #No result
• $s4a| ForEach-Object {Select Name} #No result

Thanks heaps

Answer 1

Essentially, it's because your syntax is incorrect for each of the statements that aren't working. In each of the non-working examples, you are not properly referencing the object that you wish the view the 'name' property on.

Select-Object is generally used when accepting an input object from the pipeline but can also identify the object using the -InputObject parameter.

When calling an object property by $object.propertyName, you don't need a select statement.

Instead of ForEach ($name in $s4a) {Select Name} , try this: ForEach ($name in $s4a) {$name | Select Name} ForEach ($name in $s4a) {$name | Select Name}

Instaed of ForEach ($name in $s4a) {Select $name.Name} , try this: ForEach ($name in $s4a) {$name.Name}

Instead of $s4a| ForEach-Object {Select$_.Name} $s4a| ForEach-Object {Select$_.Name} , try this: $s4a| ForEach-Object {$_.Name} $s4a| ForEach-Object {$_.Name}

Instead of $s4a| ForEach-Object {Select Name} $s4a| ForEach-Object {Select Name} , try this: $s4a| ForEach-Object {$_ | Select Name} $s4a| ForEach-Object {$_ | Select Name}

Also, please note that there is a difference in how each method returns information. Select statements return modified versions of the original objects that only contain the properties that you are selecting. Whereas, calling a property directly returns only the value of that property.