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01-18-2016 12:59 AM

**data** a;

input name $8. level **1.**;

cards;

Alfred 1

Alice 2

Barbara 2

Carol 3

Brut 4

Kelly .

Juan 1

;

**run**;

**data** exp;

set a;

if level =**.** then exp = 'Unknown';

else if level = **1** then exp = 'Low';

else if level= **2** or **3** then exp ='Medium';

else exp = 'high';

**run**;

The output dor dataset exp is as below:

name | level | exp |

Alfred | . | Unknown |

Alice | 2 | Medium |

Barbara | 2 | Medium |

Carol | 3 | Medium |

Brut | 4 | Medium |

Kelly | . | Unknown |

Juan | 1 | Low |

Not sure why for level 4 exp is 'Medium'?

Accepted Solutions

Solution

01-18-2016
09:41 PM

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01-18-2016 02:01 AM - edited 01-18-2016 02:02 AM

`else if level= 2 or 3 then exp ='Medium';`

is translated as

`if (level = 2) or (3)`

Now, in SAS the boolean value of "false" is represented by the number zero; any other numerical value means "true". "3" is therefore always true, and makes the whole condition always true, meaning that the branch for "high" will never be entered.

Edit: Heh, Josh beat me to it.

---------------------------------------------------------------------------------------------

Maxims of Maximally Efficient SAS Programmers

How to convert datasets to data steps

How to post code

Maxims of Maximally Efficient SAS Programmers

How to convert datasets to data steps

How to post code

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01-18-2016 01:26 AM

You would need to use the 'in' operator or list out each condition of the 'or' operator for the 'Medium' assignment.

```
else if level in(2 3) then exp ='Medium';
/* or */
else if level = 2 or level = 3 then exp = 'Medium';
```

I would also recommend you take a look at PROC FORMAT. It is useful for assignment logic like this.

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Posted in reply to JoshB

01-18-2016 01:32 AM

Thanks for the solution, but I am intrested in understanding why exp for level 4 is 'Medium' when datastep written in that way.

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01-18-2016 01:40 AM

Not 100% sure, but my hunch is that the expression is being evaluated like so..

if (level = 2) or ( 3 )

For your observation in question, level = 2 is evaulated as false, but (3) on it's own is always true. It would be like saying if 3 ^= .

The if statement returns a value of true, thus the assignment of 'Medium' takes place.

Solution

01-18-2016
09:41 PM

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01-18-2016 02:01 AM - edited 01-18-2016 02:02 AM

`else if level= 2 or 3 then exp ='Medium';`

is translated as

`if (level = 2) or (3)`

Now, in SAS the boolean value of "false" is represented by the number zero; any other numerical value means "true". "3" is therefore always true, and makes the whole condition always true, meaning that the branch for "high" will never be entered.

Edit: Heh, Josh beat me to it.

---------------------------------------------------------------------------------------------

Maxims of Maximally Efficient SAS Programmers

How to convert datasets to data steps

How to post code

Maxims of Maximally Efficient SAS Programmers

How to convert datasets to data steps

How to post code