There are three types of columns you can create when you click the Add Column Button in the Table Editor i.e. Statistic, Keyword and Formula columns. In each case you can name the column, define it as a control value, hide it from the finished table and format the output according to criteria of your choice. Click here for details.

If you select the Formula tab, you will see the following...

Here you can construct a formula that will appear as a column in your finished table. The calculation will be applied to each population through which the Table Editor iterates when it builds the table.

You can include values appearing in other columns in your formula by including the column name in your formula. The names of other columns in the table editor are listed in the Insert Reference drop-down box. Click on the column name you want to include in your formula. The column name will be inserted in the formula window.

A table formula can be any operation on other columns in the table (only columns which do not depend on the current column can be chosen; i.e., you can't have recursive relationships).

Column references
A column reference has the format "<Column name>", where "name" is a user-defined column name. This appears in the last column of the table definition window. Before a formula can use a table column, it must be assigned a custom name. It will then show up in the Insert Reference list. See this page for instruction on naming columns.

A column reference can also specify a specific row in the final spreadsheet. So a formula such as:
<column "MeanCD4"> * 2
will generate a new column in the table whose values are always twice the value in the "MeanCD4" column. For each row in the output table, the formula computes the value of "MeanCD4" column in the current row, and multiplies by 2.

Square brackets allow you to specify a particular population, the formula:
<column "MeanCD4"[1]> * 2
will generate a column where all of the values are twice the first entry in the "MeanCD4" column. Let's assume the first row in the output table is the control sample, then:
<column "MeanCD4"> / <column "MeanCD4"[1]> * 100
Gives an output value which is the percent of control sample (first in the table).

Row references can also be "relative" to the current row. Thus:
<column "MeanCD4"> - <column "MeanCD4"[-1]>
will generate an output column where each cell represents the difference between the current and the previous row's values for "MeanCD4".
<column "MeanCD4"> - <column "MeanCD4"[+1]>
is the same, but references the subsequent row in the final table.

Insert Function

Select the Insert Function drop-down menu shown at the left, to add function notation to your formula. There is a wide variety of functions that can be used in FlowJo Table Editor formulas. Some of these functions operate on numbers, and some on text. FlowJo is reasonably clever at converting strings to numbers and vice versa if needed, but there are two functions that do this explicitly just in case. char -> converts numbers in text form to arabic numerals and num -> converts arabic numerals to their text form.

Simple math functions:
+, -, /, * Are self-explanatory.
% = modulus: e.g., 7 % 2 = 1.

Numeric functions:
Abs(x): returns absolute value of x.
ceil:rounds up to the next whole number
floor: rounds down to the next whole number
Neg(x): returns the negative of x (or "-x").
min(x1, x2, .);
max(x1, x2, ..): These return the minimum or maximum value of the 2 or more parameters.
round:

Transcendental functions:
pow(x) is "e" raised to the power of x.
exp(x) is "e" raised to the power of x.
Ln(x) is the base-e log of x.
Log(x) is the base-10 log of x.
sqrt(x) is the square root of x.

Trigonometric functions:
acos: Arc cosine
asin: Arc sine
atan:Arc tangent
cos:Cosine
cosh:Hyperbolic cosine
sin:Sine
sinh:Hyperbolic sine
tan:Tangent
tanh:Hyperbolic tangent

Textual (String) functions:
Note that string constants must be specified in single quotes. Any text that is not in single quotes is considered to be a variable or table column reference!
+: concatenate. 'Abc' + 'def' = 'Abcdef'
Char(x): converts a number to a string: char(123) = '123'
Cont(a, b): returns 1 if a contains b
Del(a, b, c): delete from a starting at position b with length c: del('abcd', 2, 2) returns 'ad'.
End(a, b): returns 1 if a ends with b, otherwise 0.
find(x, y): finds the first position of substring y in string x: find('abce', 'c') = 3.
Ins(a, b, c): insert b into a at position c. ins('abcd', 'x', 2) returns 'axbcd'.
Len: returns the length of the string in number of characters
Lowr(a): returns the lowercase equivalent of a
Max(x1, x2, .);
Min(x1, x2, .): return the alphabetically last or first of the parameters
Num(x): converts a string to a number: num('123') = 123
Rep(a, b, c): replace the first instance of b in a with c: rep1('ababab', 'a', 'c') returns
Repall(a, b, c): replace all instances of b in a with c: repl('ababab','a', 'c') returns 'cbcbcb'. Strt(a, b): returns 1 if a starts with b, otherwise 0. Strt('abcd', 'ab') = 1
Sub(x, a, b): substring of string x, starting at position a, of length b. sub('abc' 2, 1) = 'b'
Trun(a, b): truncates a to a length of b characters. If b is less than zero, then delete the last '-b' characters from a. Trun('abc', -1) = 'ab'.
Uppr(a): returns the uppercase equivalent of a
Word(x, a, b): selects word number a from string x, using b as a delimiter: word('this is fun', 2, ' ') returns "is".

Logical functions:
All of these functions return a 1 if true or a 0 if false.
<, >,<=, >=, =, !=
Thus, the expression "a < b" returns 1 if a is less than b, otherwise zero.
&&: and: a & b: if both a and b are nonzero, then 1, otherwise 0
||: or: a || b: if either a or b are nonzero, then 1, otherwise 0
!: not: !A: if A = 0, then 1, otherwise 0

Conditional functions:
Ifthen(a,b,c): If the expression a evaluates to nonzero, then return expression b, otherwise expression c

Click OK and your column definition will be added to the Table Editor. For help with other aspects of the Add Column tool, click here.

To change the characteristics of the column you have defined click on the Column Info button in the Table Editor.