Hey,

New psychopy3 user here in need of some help.

I am trying to randomize the pairing of two stimuli images that flash on the screen at the same time for a total of 60 trials. Within these 60 trials I need to fulfill these 3 cases:

- a cupcake on the left and a muffin on the right 15 times
- a muffin on the left and a cupcake on the right 15 times
- a cupcake on the left and a cupcake on the right 30 times

I have both 8 cupcake images and 8 muffin images (excel file below) that need to be randomly paired together to meet these 3 criteria:

At the very beginning of the experiment I’ve set up a routine with some code that does the following:

```
import random, xlrd
random.seed()
in_file = 'cupmuf_database.xlsx'
num_items = 8
num_tests = 60
cur = 0
```

After some instructions for participants comes my trial routine.

In begin routine:

```
inbook = xlrd.open_workbook(in_file)
insheet = inbook.sheet_by_index(0)
cases = ["c_cupR_mufL","c_mufR_cupL","c_cupL_cupR"]
cup_stim = []
muf_stim = []
c_cupR_mufL_count = 15
c_mufR_cupL_count = 15
c_cupL_cupR_count = 30
left = []
right = []
correct=[]
for rowx in range(1,num_items+1):
row = insheet.row_values(rowx)
cup_stim.append(row[0])
muf_stim.append(row[1])
for x in range(60):
if (c_cupR_mufL_count == 0 and "c_cupR_mufL" in cases):
cases.remove("c_cupR_mufL")
if (c_mufR_cupL_count == 0 and "c_mufR_cupL" in cases):
cases.remove("c_mufR_cupL")
if (c_cupL_cupR_count == 0 and "c_cupL_cupR" in cases):
cases.remove("c_cupL_cupR")
ran = random.randrange(0, len(cases))
test = cases[ran]
if (test == "c_cupR_mufL"):
right.append(cup_stim[random.randrange(1, 8)])
left.append(muf_stim[random.randrange(1, 8)])
c_cupR_mufL_count = c_cupR_mufL_count - 1
correct.append(1)
if (test == "c_mufR_cupL"):
left.append(cup_stim[random.randrange(1, 8)])
right.append(muf_stim[random.randrange(1, 8)])
c_mufR_cupL_count = c_mufR_cupL_count - 1
correct.append(1)
if (test == "c_cupL_cupR"):
leftVal = random.randrange(1, 8)
rightVal = random.randrange(1, 8)
if leftVal == rightVal:
if rightVal == 8:
rightVal = rightVal - 1
else:
rightVal = rightVal + 1
left.append(cup_stim[leftVal -1])
right.append(cup_stim[rightVal -1])
c_cupL_cupR_count = c_cupL_cupR_count - 1
correct.append(0)
```

In end routine:

```
thisExp.addData('left', left[cur])
thisExp.addData('right', right[cur])
thisExp.addData('correct', correct[cur])
if key_resp_2.keys == "left" and correct[cur] == 1:
thisExp.addData('res', 1)
else:
thisExp.addData('res', 0)
if left[cur] == muf_stim or right[cur] == muf_stim:
isTarget = 1
else:
isTarget = 0
cur = cur + 1
```

My loop is set for nReps to equal $num_tests (which I’ve defined as 60).

When I run this I do get 60 trials each time and all 8 cupcake and muffin images are being used but I don’t get the correct number of pairings for each of my 3 cases. For example, I’ll get 23 cupcake left and cupcake right instead of 30 cupcake left and cupcake right.

I hope this was enough information, I can clarify if something doesn’t make sense.

Thanks in advance.