Module 4: Filtering Results and Manipulating Data

Question 1

What does the eval command allow you to do?

Answer 1

The eval command allows you to calculate and manipulate field values in your report and it supports a variety of functions

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Question 2

What happens if the destination field exists when using the eval command?

Answer 2

The values of the field are replaced by the results of eval command

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Question 3

Is the index data modified when using the eval command?

Answer 3

No, the data is not modified and no new data is written into the index

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Question 4

Are field values treated as case sensitive when using the eval command?

Answer 4

Yes, field values are treated in a case sensitive manner when using the eval command

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Question 5

Three things the eval command allows you to?

Answer 5

• Calculate expressions
• Place the results in a field
• Use that field in searches or other expressions

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Question 6

What are the operator types that the eval commands effects?

Answer 6

Arithmetic/Operators
+, -, *, /, %

Concatenation/Operators
+, .

Boolean/Operators
AND OR NOT XOR

Comparison/Operators
, <=, >=, !=, =, ==, LIKE

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Question 7

What is another function the eval command can do to values?

Answer 7

It can convert values. For example, the eval command can convert bytes into megabytes

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Question 8

The eval command must do what in order to successfully convert values?

Answer 8

It must be set to a new or existing field

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Question 9

The eval command also has another function that will help readability?

Answer 9

The round (field/number, decimals) function sets the value of a field to the number of decimals you specify

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Question 10

What will the result be if decimals are unspecified when using the round function in the eval command?

Answer 10

The result is a whole number will be present

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Question 11

What command would you use if you wanted to remove a field in the search window?

Answer 11

Use the fields - command

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Question 12

You can perform mathematical functions against fields with what when using the eval command?

Answer 12

You can use mathematical functions against fields with numeric field values

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Question 13

When using the eval command, what does the tostring function allow you to do?

Answer 13

tostring allows you to convert a numeric field value to a string
example: tostring(field, “option”)

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Question 14

What are some of the options of the tostring function when using the eval command?

Answer 14

• “commas”: applies commas. If the number includes decimals, it rounds to two decimal places
• “duration”: formats the number as “hh:mm:ss”
• “hex”: formats the number in hexadecimal

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Question 15

When using the eval command, give a scenario where you would use the range function?

Answer 15

Use the range function to return the difference between the max and min values of _time

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Question 16

True or False: eval with added characters converts numeric field values to strings?

Answer 16

Yes it does

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Question 17

When formatting and sorting values numerically what is the proper order to accomplish this?

Answer 17

To order numerically, first sort, then use eval command

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Question 18

Can multiple expressions be used in the eval command?

Answer 18

Yes multiple expressions can be used in the eval command

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Question 19

What are some of the rules when using expressions with the eval command?

Answer 19

• Each subsequent expression references the results of previous expressions
• Expressions must be separated by commas
  example: eval fieldname1 = expression1,
  fieldname2 = expression2,
  fieldname3 = expression3

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Question 20

What are some of the rules when using the if function with the eval command?

Answer 20

• The if function takes 3 arguments (X,Y,Z)
• The first argument, X, is a Boolean expression
• If it evaluates to TRUE, the result evaluates to the second argument, Y
• If it evaluates to FALSE, the result evaluate to the 3rd argument, Z

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Question 21

What must be included with non-numeric values (arguments) when using the if function with the eval command?

Answer 21

Non-numeric values must be enclosed in “double quotes”

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Question 22

Are field values treated in a case sensitive manner when using the if function with the eval command?

Answer 22

Yes they are case sensitive

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Question 23

How would you use the case function with the eval command?

Answer 23

case(X1, Y1, X2, Y2…)

• the 1st argument, X1, is a Boolean expression
• if it evaluates to TRUE, the result evaluates to Y1
• if it evaluates to FALSE, the next Boolean expression, X2, is evaluated, etc.
• if you want an “otherwise: clause, just test for a condition you know is true at the end
  (e. g., 0=0)

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Question 24

Explain when and how to use the eval function?

Answer 24

You would use the eval function to count the number of events that contain a specific field value, use the count and eval functions

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Question 25

With eval, then using a transforming command like stats what is required?

Answer 25

• An as clause is required
• Double quotes are required for character field values
• Field values are case sensitive

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Question 26

What are some of the attributes of the search command?

Answer 26

• Treats field values in a case insensitive manner
• Allows searching on keyword
• Can be used at any point in the search pipeline

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Question 27

What are some of the attributes of the where command?

Answer 27

• Can compare values from two different fields
• Functions are available, such as isnotnull()
• Treats field values in a case sensitive manner
• Can not appear before the first pipe in search pipeline

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Question 28

How does the search command behave when used?

Answer 28

It behaves exactly like search strings before the first pipe and it can also use the “*” wildcard

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Question 29

How does the where command behave when used?

Answer 29

• Uses same expression syntax as the eval command
• Uses boolean expressions to filter search results and only keeps results that are True
• Double quoted strings are interpreted as field values (treats field values in a case sensitive manner)
• Unquoted or single-quoted strings are treated as fields

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Question 30

True or False: The where command is also used to compare two different fields?

Answer 30

True

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Question 31

True or False: Can you do wildcard searches with the where command?

Answer 31

True

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Question 32

In what situation would you use (_) and (%) when using the where command?

Answer 32

You would use the “_” for one character and “%” for multiple characters

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Question 33

What must you use with wildcards when using the where command?

Answer 33

You must use the “like” operator

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Question 34

When would you use the fillnull command?

Answer 34

You would use the fillnull command to replace null values in fields

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Question 35

How would you specify a string you wanted to display when using the fillnull command?

Answer 35

You use the value=string
example: fillnull value=NULL

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Question 36

What happens if you don’t have a value= clause when using the fillnull command?

Answer 36

The default replacement value is 0

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Question 37

How would you restrict which fields fillnull command would apply?

Answer 37

By listing them at the end of the command
example: fillnull VALUE=”N/A” discount refund

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