expr
Evaluate a mathematical expression
Description
Evaluate an expression using a C-like language. Variables and operators are used to create output values.
Discussion
Use the expr object to perform mathematical calculations using C language-style mathematical operations. The object evaluates expressions that use the "variables" $i1-$i9 (the first to ninth inlets, taken as integers), $f1-$f9 (the inlets as floats) and $s1-$s9 (the inlets as symbols), and/or constants of the same types. The operators are +, -, *, /, &, |, &&, ||, !, ~, and ^, and you can also use a set of predefined mathematical and statistical functions. The list of functions in expr are as follows: min, max, int (convert to integer), float (convert to float), pow (power), sqrt (square root), exp (power of e to x), log10 (log), ln (natural log), log (nat. log), sin, cos, tan, asin (arcsin), acos, atan, atan2, sinh, cosh, tanh, fact (factorial), random, round, floor, ceil, size (size of a table), sum (sum of table contents), Sum (sum with boundaries), avg (of table contents), Avg (avg with boundaries), store (store into a table).
Arguments
expression[list]
optional
The argument to the expr object is a mathematical expression composed of numbers, arithmetic operators such as + or *, comparisons such as < or > , C functions such as min () or pow () , names of table objects, and changeable arguments ( $i , $f , and $s ) for ints, floats, and symbols received in the inlets.
constant[number]
optional
Numbers can be used as constants in the mathematical expression.
inlet-format[symbol]
optional
Changeable arguments that specify data formats associated with an inlet are described using a combination of a data type ( $i or $f ) and an inlet number (example: $i2 ). The argument will be replaced by numbers received in the specified inlet.
table-info[$s]
optional
Changeable arguments that specify accessing data from a table are described using the argument $s and an inlet number which is replaced by the name of a table to be accessed. The argument should be immediately followed by a number in brackets specifying an address in the table. (Examples: $s2[7] or $s3[$i1] .)
(other)[symbol]
optional
The expr object understands the following arithmetic operators: + , - , * , / , %. Other operators are ~ (one's complement), ^ (bitwise exclusive or), & , && , | , || , and ! (not).
Attributes
Common Box Attributes
annotation[symbol]
Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.
background[int]: 0
Adds or removes the object from the patcher's background layer. background 1 adds the object to the background layer, background 0 removes it. Objects in the background layer are shown behind all objects in the default foreground layer.
color[4 floats]
Sets the color for the object box outline.
fontface[int]
Sets the type style used by the object. The options are:
plain
bold
italic
bold italic
Possible values:
0 = 'regular'
1 = 'bold'
2 = 'italic'
3 = 'bold italic'
fontname[symbol]
Sets the object's font.
fontsize[float]
Sets the object's font size (in points).
Possible values:
'8'
'9'
'10'
'11'
'12'
'13'
'14'
'16'
'18'
'20'
'24'
'30'
'36'
'48'
'64'
'72'
hint[symbol]
Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.
ignoreclick[int]: 0
Toggles whether an object ignores mouse clicks in a locked patcher.
jspainterfile[symbol]
You can override the default appearance of a user interface object by assigning a JavaScript file with code for painting the object. The file must be in the search path.
patching_rect[4 floats]: 0. 0. 100. 0.
Sets the position and size of the object in the patcher window.
position[2 floats]
write-only
Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.
presentation[int]: 0
Sets whether an object belongs to the patcher's presentation.
presentation_rect[4 floats]: 0. 0. 0. 0.
Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.
rect[4 floats]
write-only
Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).
size[2 floats]
write-only
Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.
textcolor[4 floats]
Sets the color for the object's text in RGBA format.
textjustification[int]
Sets the justification for the object's text.
Possible values:
0 = 'left'
1 = 'center'
2 = 'right'
varname[symbol]
Sets the patcher's scripting name, which can be used to address the object by name in pattr, scripting messages to thispatcher, and the js object.
Messages
bang
In left inlet: Evaluates the expression using the values currently stored.
int
The number received in each inlet will be stored in place of the $i or $f argument associated with it. (Example: The number in the second inlet from the left will be stored in place of the $i2 and $f2 arguments, wherever they appear.)
- input
[int]
(inlet1)
See the int listing.
- input
[int]
(inlet2)
See the int listing.
- input
[int]
(inlet3)
See the int listing.
- input
[int]
(inlet4)
See the int listing.
- input
[int]
(inlet5)
See the int listing.
- input
[int]
(inlet6)
See the int listing.
- input
[int]
(inlet7)
See the int listing.
- input
[int]
(inlet8)
See the int listing.
- input
[int]
(inlet9)
See the int listing.
- input
[int]
float
The number in each inlet will be stored in place of the $f or $i argument associated with it. The number will be truncated by a $i argument.
- input
[float]
(inlet1)
See the float listing.
- input
[float]
(inlet2)
See the float listing.
- input
[float]
(inlet3)
See the float listing.
- input
[float]
(inlet4)
See the float listing.
- input
[float]
(inlet5)
See the float listing.
- input
[float]
(inlet6)
See the float listing.
- input
[float]
(inlet7)
See the float listing.
- input
[float]
(inlet8)
See the float listing.
- input
[float]
(inlet9)
See the float listing.
- input
[float]
set
If the word set precedes the items of a list received in the left inlet, the list of numbers are treated as if each had come in a different inlet, replacing the stored value with the new value. However, the expression is not evaluated and nothing is sent out the outlet. If there are fewer numbers in the message than there are inlets, the stored value in each remaining inlet stays unchanged.
- input
[list]
sm1
See the symbol listing.
- table
[list]
sm2
See the symbol listing.
- table
[list]
sm3
See the symbol listing.
- table
[list]
sm4
See the symbol listing.
- table
[list]
sm5
See the symbol listing.
- table
[list]
sm6
See the symbol listing.
- table
[list]
sm7
See the symbol listing.
- table
[list]
sm8
See the symbol listing.
- table
[list]
sm9
See the symbol listing.
- table
[list]
symbol
list
The items of a list received in the left inlet are treated as if each had come in a different inlet, and the expression is evaluated. If the list contains fewer items than there are inlets, the most recently received value in each remaining inlet is used. Any of the above messages in the left inlet will evaluate the expression and send out the result. If a value has never been received for each changeable argument, that value is considered 0 when the expression is evaluated. The number of inlets is determined by how many changeable arguments are typed in. The maximum number of inlets is 9.
- input
[list]
Output
float
The output is the result of the evaluated expression.
int
The output is the result of the evaluated expression.
See Also
| Name | Description |
|---|---|
| if | Conditional statement in if/then/else form |
| vexpr | Evaluate a math expression for a list |
| round | Round to a value |