Excel - How to count the number of sign changes (from + to - or vice versa) in a column?

Suppose you have a column of numbers and the data can be positive or negative. How do you count the number of times the data changes from positive to negative, or vice versa?

We will use three functions, SIGN, INT and SUM to solve the problem.


First we add a helper column B, name it "sign", then use SIGN function to get its sign. If the data is positive, it returns 1. If the value is negative, it returns -1. The formula is like:

=SIGN(A2)

Then we add another helper column C, call it "sign change", which checks whether sign of the current value is different from the last value. INT function is used to return the logical value TRUE or FALSE into 1 or 0.

At last, at the end of column C, we use a SUM function to sum all the value changes. In this example, the data sign changes for 4 times (-1 to -3, -3 to 4, 2 to -5, and -5 to 6).


VBA method

Below is the VBA code to achieve it. You need to add a clickable button on the spreadsheet and assign the following code to it.

Private Sub CommandButton1_Click()
    Dim total_change As Integer
    total_change = 0
    Dim sign As String
    Dim last_sign As String
    Dim row As Integer
    last_sign = "positive"
    If Cells(2, 1) < 0 Then
        last_sign = "negative"
    End If
    For row = 3 To 7
        sign = "positive"
        If Cells(row, 1) < 0 Then
            sign = "negative"
        End If
        If last_sign <> sign Then
            total_change = total_change + 1
        End If
        last_sign = sign
    Next
    MsgBox ("total sign change=" & total_change)
End Sub

Comments

Post a Comment

Popular posts from this blog

Excel - IF function

Image
If function is a logic function. It does two things: Whether the criteria is met Return a value based on whether the criteria is met or not. If the criteria is met, it returns one value; if the criteria is not met, it returns a different value. The reason IF function is confusing for some Excel users is that it does two things: a logical test, AND a return value depending on the logical test result, while the name of "IF" implies it only does a logical test. If this function only returns TRUE or False, it would be much easier to understand. In the following example, there are 5 employees, each having his own budget. Column C records the exact amount of money they spent. If the actual spending is greater than budget, we call it "Over budget", otherwise, we call it "Within budget". The IF function is: =IF(C2>B2,"Over budget","Within budget") The first part, "C2>B2", is a logical test. If this is TRUE, then the IF function ...
Read more

Excel - VLOOKUP function

Image
This post is written by Yisong Geng, PhD at Calc LLC. If you need consulting services with Excel, please  contact us . VLOOKUP is one of the most commonly used Excel functions. VLOOKUP function asks for 4 things: The value you want to look up, such as name of a person The data range you want to search If the value is found in the data range, which column contains the value you want the function to return? Whether it is a approximate match or not. The default option is approximate match. This argument is optional and let's ignore it for now. The following table contains first name, last name and age of 4 people. Your task is to find the age of Jan Doe. It can be easily done using VLOOKUP function. The value you want to look up is "Jane", which is at cell "A3" The range of data you want to search, which is "A2:C5" Which column contains the value you want to retrieve? The "Age" is column C, so this argument is 3. The 4th argument is optional and...
Read more

Excel - Hierarchical chart (Treemap)

Image
If you have hierarchical data, you can create beautiful hierarchical charts. For example, in a university, there are students of different majors in departments, and departments in schools. Suppose we have data below, showing number of students in each school, department and major. In this example, we show you how to make treemap chart. The other type of hierarchical chart is sunburst chart. The data is equivalent if all the cells are filled. I like the following format better. 1. Select the data, then click Insert > Charts > Other Charts > Hierarchical . Select Treemap .  2. A nice-looking treemap chart is shown. The blue area shows all engineering students. The orange area shows all business students. Size of each rectangle is proportional to the number of students in each major.
Read more