Nested Loop Functions in Excelby James Highland
Microsoft Excel is a powerful application that offers many tools for analyzing and manipulating data. The formula engine in Excel is particularly versatile for processing stored data. Formulas can be basic, but they also offer complex programming capabilities, such as the use of nested loops. Nesting functions allows a single formula to perform multiple decision-making algorithms for many possible outcomes.
One of the most popular functions for creating nested loops is the "if()" function. Nesting occurs when any function is placed inside another instance of the same function. "If()" functions are particularly well-suited to this programming style. A single "if()" function makes one decision to offer two possible outcomes. However, in some cases it is necessary for a formula to make multiple decisions and generate any of many possible outcomes. In order to achieve these, one "if()" statement must be constructed inside another "if()" statement. For example, suppose you have a cell with a person's age. You need Excel to label the individual as either a "Minor," an "Adult" or a "Senior." The first "if()" statement determines if they are under the age of 18. If so, the second "if()" statement then determines if they are over the age of 65. The formula would include the second "if()" inside the first as '=if(a1<18,"Minor",if(a1>=65,"Senior","Adult"))'. This creates a decision loop from the nested functions.
"And()" and "Or()"
It is possible to nest "and()" and "or()" Excel functions to isolate particular cells that meet certain criteria. Suppose you have a column of names, with two additional columns for their sex and age. If you were performing a medical study and needed to quickly find eligible patients, you could nest these functions. For example, if you needed women between the ages of 20 and 30, and men between the ages of 25 and 35, nesting "and()" and "or()" statements within a single "if()" statement could find the candidates. In this case, the formula might read '=if(or(and(b2="female",c2>=20,c2<=30),and(b2="male",c2>=25,c2<=35)),"Candidate","")'. The nesting of multiple "and()" statements within an "or()" statement, which is subsequently nested inside an "if()" statement, allows Excel to analyze all the variables to produce the results using these loops.
Parsing characters from text is often necessary in Excel to extract first names or last names from a cell that contains a full name. This is easily accomplished using nested functions that operate on text. For example, if a cell contains a full name with a space between each name, you can nest a text searching function to find the space and nest this inside a text-parsing function, which extracts part of a cell's content. The formula could read '=left(a1,search(a1," "))'. The "search()" function locates a space, returns its position in the cell, and this result is then nested inside the "left()" function, which extracts the first set of characters leading up to that space. Nesting text functions can be particularly efficient. The alternative is to break up these formulas into multiple cell formulas that each separately determine a part of the process. This could use up many unnecessary cells in your spreadsheet when the entire process could otherwise be accomplished with one nested formula.