The Inquisit expression language includes a number of commonly used mathematical functions that perform various calculations, from rounding decimal numbers to the nearest integer to computing a number's arctangent.
| Function | Description | Examples | Result |
|---|---|---|---|
| abs | Returns the absolute value of the argument |
abs(-1) |
1 |
| mod | Returns the floating point remainder when the first argument is divided by the second |
mod(1.33, 1) mod(9, 4) |
0.33 1.0 |
| ipart | Returns the integer portion of a floating point argument |
ipart(3.14) |
3 |
| fpart | Returns the fractional portion of a floating point argument |
fpart(3.14) |
0.14 |
| min | Returns the minimum value of the arguments |
min(0, 1, 2, 3) min(-100, -1000) |
0 -1000 |
| max | Returns the maximum value of arguments |
max(0, 1, 2, 3) max(-100, -1000) |
3 -100 |
| pow | Returns the first argument to the power of the second argument |
pow(3, 3) pow(10, 2) |
27 100 |
| sqrt | Returns the square root of the argument | sqrt(4) | 2 |
| sin | Returns the sine of the argument | sin(1.570796) | 1 |
| sinh | Returns the hyperbolic sine of the argument | sinh(1.570796) |
2.301299 |
| asin | Returns the arcsine of the argument | ||
| cos | Returns the cosine of the argument | cos(1.570796) | 0 |
| cosh | Returns the hyperbolic cosine of the argument | cosh(1.570796) | 2.509178 |
| acos | Returns the arccosine of the argument | ||
| tan | Returns the tangent of the argument | tan(0.785398) | 1 |
| tanh | Returns the hyperbolic tangent of the argument | tanh(1.000000) | 0.761594 |
| atan | Returns the arctangent of the argument | atan(5.0) | 1.373401 |
| atan2 | Returns the arctangent of the first argument divided by the second argument | atan2(5.0 / 5.0) | 0.99669 |
| log | Returns the base 10 logarithm of the argument | log(9000.00) | 9.104980 |
| ln | Returns the natural logarithm of the argument | ln(9000.00) | 3.954243 |
| exp | Returns the exponential values of the argument | exp(2.302585) | 10.0 |
| logn | Returns the logarithm of the first argument using the second argument as the base | ||
| round | Rounds the argument to the nearest integer |
round(1.49) round(1.50) |
1 2 |
| ceil | Rounds the argument up to the nearest integer |
ceil(1.49) ceil(1.50) |
2 2 |
| floor | Rounds the argument down to the nearest integer |
floor(1.49) floor(1.50) |
1 1 |
| deg | Converts an argument from radians to degrees | ||
| rad | Converts an argument from degrees to radians | ||
| rand | Generates a random number within a given range |
rand(0, 1) rand(0, 100) |
0.55678 97.12314 |
| randgaussian | Generates a random number from a guassian distribution with the given mean and sd |
randgaussian(50, 16) randgaussian(0, 10) |
55 -4.33 |
The following block rounds the mean latency down to an integer and saves it to a value:
<block myblock>
/ trials=[1-5=practicetrial; 6-10=testtrial)]
/ onblockend=[values.simplemean = round(block.myblock.meanlatency)]
</block>
The following block finds the best performance from 3 different trial types and saves the result to a value.
<block myblock>
/ trials=[1-300=noreplace(t1, t2, t3)]
/ onblockend=[values.bestscore = max(trial.t1.percentcorrect, trial.t2.percentcorrect,
trial.t3.percentcorrect)]
</block>
The following table lists functions for selecting randomly or otherwise from a pool of values.
| Function | Description | Examples |
|---|---|---|
| noreplace | Randomly selects without replacement from a set of values |
noreplace(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) noreplace(0, 2.5, 5, 7.5, 10) |
| noreplacecorrect | Randomly selects without replacement if a correct response is given and with replacement if an incorrect response is given |
noreplacecorrrect(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) |
| noreplaceerror | Randomly selects without replacement if an incorrect response is given and with replacement if a correct response is given |
noreplaceerror(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) |
| noreplacenorepeat | Randomly selects without replacement or consecutive selection fo a value |
noreplacenorepeat(10, 20, 30, 40, 50, 60, 70, 80, 90, 100) noreplacenorepeat(0, .3333333, .6666667, 1) |
| replace | Randomly selects with replacement from a set of values |
replace(10, 20, 30, 40, 50, 60, 70, 80, 90, 100) replace(0, .3333333, .6666667, 1) |
| replacenorepeat | Randomly selects with replacement if an incorrect response is given and with replacement if a correct response is given |
replacenorepeat(10, 20, 30, 40, 50, 60, 70, 80, 90, 100) replacenorepeat(0, .3333333, .6666667, 1) |
| sequence | Selects the items in the specified order |
sequence(10, 9, 8, 7, 6, 5, 4, 3, 2, 1) sequence(2, 4, 6, 8, 10) |
| getitem | Returns the item at the specified index. |
getitem(counter.deck, 1) getitem(text.presenteditems, text.presenteditems.itemcount) getitem(item.useritems, item.useritems.itemcount - 1) |
| setitem | Sets the item at the specified index to the specified value. |
setitem(counter.deck, values.currentcard, 10) setitem(text.presenteditems, text.targets.currentitem, text.presenteditems.itemcount) setitem(item.useritems, values.firstresponse, 1) |
| insert | Inserts an item of the specified value into the specified index. |
insert(counter.deck, values.currentcard, 2) insert(text.presenteditems, text.targets.currentitem, 1) insert(item.useritems, values.firstresponse, 1) |
| remove | Removes item at the specified index. |
remove(counter.deck, 10) remove(text.presenteditems, text.presenteditems.itemcount) remove(item.useritems, item.useritems.itemcount - 1) |
| clear | Removes all items from a stimulus or counter. |
clear(counter.deck) clear(text.response) clear(item.useritems) |
| reset | Resets a counter. If the counter selects without replacement, all items are returned to the selection pool. If selection is sequential, the first item in the pool is selected next. |
reset(counter.odds) reset(picture.faces) |
The following stimulus will be presented in a randomly selected position on the screen:
<picture mypic>
/ items = ("foo.jpg")
/ hposition = replace(0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%)
/ vposition = replace(0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%)
</picture>
The following trial has a response timeout that gets 50 milliseconds shorter each time the trial is run.
<trial mytrial>
/ stimulustimes = [1=target]
/ timeout = sequence(1000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500)
/ response = ("a", "b")
</block>
The following table lists functions for analyzing and manipulating strings of text.
| Function | Description | Examples | Result |
|---|---|---|---|
| tolower | Converts all alphabetic characters in the string to lower case. |
tolower("TURNIPS") tolower("Sales@Server.Com") |
turnips sales@server.com |
| toupper | Converts all alphabetic characters in the string to upper case. |
toupper("turnips") |
TURNIPS |
| capitalize | Converts the first letter of each word in the string to upper case. This is useful for presenting proper nouns entered by the participant. |
capitalize("john") capitalize("bill gates") capitalize(tolower("dIET cOKE")) |
John Bill Gates Diet Coke |
| concat | Contenates two strings together. |
concat("basket", "ball") |
basketball United States |
| search | Searches the first string for any occurrence of the second string. If the string is found, it returns the zero based index of the first occurrence. If the string is not found, it returns -1. |
search("benjamin", "ben") search("benjamin", "benji") search("benjamin", "jamin") |
0 -1 3 |
| replaceall | Searches the first string for all occurrences of the second string and replaces them with the third stringFinds all occurrences of the Randomly selects with replacement from a set of values |
replaceall("Hello %name%", "%name%", "Julia") replaceall("old old old", "old", "new") |
Hello Julia new new new |
| contains | Returns true if the first string contains the second string, otherwise false. |
contains("sales@server.com", "@") |
true false |
| startswith | Returns true if the first string starts with the second string. |
startswith("https://www.millisecond.com", "http://") startswith("Four score and seven years ago", " ") |
true false |
| endswith | Returns true if the first string ends with the second string. |
endswith("All's well that ends well.", ".") endswith("Why did the chicken cross the road", "?") |
true false |
| substring | Returns a portion of the string starting at the specified start index and of the specified length | substring("www.millisecond.com", 4, 11) | millisecond |
| trim | Trims the characters in the second string from the beginning and end of the first string |
trim(" hello ", " ") |
hello |
| trimright | Trims the characters in the second string from the right side of the first string |
trimright("Get into the chopper!", "!?.") |
Get into the chopper |
| trimleft | Trims the characters in the second string from the left side of the first string |
trimleft("$1.00", "$")) |
1.00 |
| length | Returns the length of the string |
length("123") length("54321") |
3 5 |
| format | An advanced function that allows string substitutions and formatting of decimals using format strings as used by the C function printf. |
format("You have %i points", 16) format("%.2f", 3.14159265) |
You have 16 points 3.14 |
| evaluate | An function that evaluates a string as an expression and returns the result. |
evaluate("(1 + 6) * 5") evaluate(text.mathproblems.currentitem) - evaluate(text.mathproblems.currentitem) |
35 0 |
The following stimulus will be presented in a randomly selected position on the screen:
<surveypage mypage>
/ caption = format
/ questions = [1=firsname; 2=lastname]
/ ontrialend = [text.firstname.item = capitalize(lower(textbox.firstname.response))]
</surveypage>
The following trial has a response timeout that gets 50 milliseconds shorter each time the trial is run.
<block myblock>
/ trials = [1-100=test]
/ branch = [if( contains(textbox.college.response, "Cornell")
== true ) block.next]
</block>
The following table lists functions that calculate performance metrics and statistics. Many elements contain properties corresponding to these functions. The benefit of the functions is that they can compute performance metrics for combinations of elements, whereas the property returns the metric for its element only.
Consider, for example, a task involving two types of trials, a target trial and distractor trial. Using the totalpercentcorrect property, we can get the percent of correct responses on either trial element. Specifically, the expression "trial.target.totalpercentcorrect" returns the percentage for target trials, and "trial.distractor.totalpercentcorrect" returns percentage for distractor trials. What if we want the percent correct for both types of trials. For this, we can use the totalpercentcorrect function. Specifically, the expression "totalpercentcorrect(trial.target, trial.distractor)" will return the percentage for the combined set of trials. These functions can be used to compute metrics for any arbitrary combination of elements.
| Function | Description | Examples |
|---|---|---|
| correctcount | number of correct responses in the current block | correctcount(trial.targeta, trial.targetb, trial.targetc) |
| count | number of times the item was run within the current block |
count(trial.foo, trial.bar, trial.foobar) |
| errorcount | number of incorrect responses in the current block | errorcount(trial.red, trial.green, trial.blue) |
| inwindowcount | number of responses occurring within the response window in the current block | inwindowcount(trial.category1, trial.category2) |
| maxlatency | maximum response latency in the current block | maxlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| meanlatency | mean response latency in the current block | meanlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| minlatency | minimum response latency in the current block | minlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| notinwindowcount | number of responses occurring outside the response window in the current block | notinwindowcount(trial.category1, trial.category2) |
| percentcorrect | percent of correct responses in the current block | percentcorrect(trial.stroopredred, trial.stroopgreengreen, trial.stroopyellowyellow, trial.stroopblueblue) |
| sdlatency | standard deviation of response latencies in the current block | sdlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| sumlatency | sum of response latencies in the current block | sumlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| selectedcount | number of selected items | selectedcount(item.targets, item.distractors) |
| totalcorrectcount | total number of correct responses | totalcorrectcount(trial.critical, trial.test) |
| totalcount | total number of times the item was run so far | totalcount(trial.soa100, trial.soa300, trial.soa500) |
| totalerrorcount | total number of incorrect responses | totalerrorcount(trial.critical, trial.test) |
| totalinwindowcount | total number of responses occurring within the response window | totalinwindowcount(trial.congruent, trial.incongruent, trial.neutral) |
| totalmaxlatency | maximum response latency | totalmaxlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| totalmeanlatency | mean response latency | totalmeanlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| totalminlatency | minimum response latency | totalminlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| totalnotinwindowcount | total number of responses outside the response window | totalnotinwindowcount(trial.congruent, trial.incongruent, trial.neutral) |
| totalpercentcorrect | percent of correct responses | totalpercentcorrect(trial.bigtargeta, trial.bigtargetb, trialbigtargetc) |
| totalpercentinwindow | percent of responses within the response window | totalpercentinwindow(trial.congruent, trial.incongruent, trial.neutral) |
| totalsdlatency | standard deviation of response latencies | totalsdlatency(block.critical1, block.critical2) |
| totalsumlatency | total sum of response latencies | totalsumlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| totaltrialcount | total number of trials run | totaltrialcount(block.training1, block.training2) |
| totalvarlatency | variance of response latencies | totalvarlatency(trial.leftlow, trial.lefthigh, trial.leftmid) |
| trialcount | number of trials run within the current block | trialcount(trial.congruent, trial.incongruent) |
| unselectedcount | number of unselected items | unselectedcount(picture.target1, picture.target2, picture.target3) |
| varlatency | variance of response latencies within the current block | varatency(trial.leftlow, trial.lefthigh, trial.leftmid) |