logical operator

A logical operator is something that applies to one or more variables and returns a TRUE/FALSE variable (a.k.a. a boolean variable).

Common logical operators

• > and >=: greater than / greater than or equal to (applies to numerical values)
• < and <=: less than / less than or equal to (applies to numerical values)
• ==: exactly equal to (can apply to non-numerical values as well)
• !=: not equal to (can apply to non-numerical values)
• &: and (applies to boolean values)
• |: or (applies to boolean values)

Example

Suppose we have the following data in df:

ID	AGE	EMPSTAT
1	18	3
2	25	1
3	30	2
4	40	1
5	50	1
6	65	2
7	70	3
8	80	3

Suppose we ran the following code:

df$EMPLOYED <- df$EMPSTAT==1
df$OLDER_THAN_25 <- df$AGE>=25
df$YOUNGER_THAN_65 <- df$AGE<=65
df$WORKING_AGE <- (df$OLDER_THAN_25==TRUE) & (df$YOUNGER_THAN_65==TRUE)

The resulting dataframe would look like:

ID	AGE	EMPSTAT	EMPLOYED	OLDER_THAN_25	YOUNGER_THAN_65	WORKING_AGE
1	18	3	FALSE	FALSE	TRUE	FALSE
2	25	1	TRUE	TRUE	TRUE	TRUE
3	30	2	FALSE	TRUE	TRUE	TRUE
4	40	1	TRUE	TRUE	TRUE	TRUE
5	50	1	TRUE	TRUE	TRUE	TRUE
6	65	2	FALSE	TRUE	TRUE	TRUE
7	70	1	TRUE	TRUE	FALSE	FALSE
8	80	3	FALSE	TRUE	FALSE	FALSE