R - If / ifElse

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If you want a:

• Scalar operation (over one value): use the if statement
• Vectorial operation (over multiple value): use the ifelse

Articles Related

Type

if

With one value

Syntax

if(cond) expr
if(cond) cons.expr  else  alt.expr

where:

• cond is a condition

Example

• Without return value

if(1>2) {
    print("1>2")
} else if(FALSE) {
    print (FALSE)
} else {
    print("2>1")
}

• With return value (Conditional Assignment)

x = if(4 > 3) { 1 } else { 0 } 

ifelse

If else takes vectors as input and return vector on output

• With the data frame df, when the TOTAL_TIME_SEC is above 200, give it the value 200.

df$TOTAL_TIME_SEC_CAPPED <-  ifelse(df$TOTAL_TIME_SEC > 200, 200, df$TOTAL_TIME_SEC)