I'm trying to update the orientation of a gratingStim every 100 ms or so in the psychopy coder. Currently, I'm updating the attribute (or trying to) with these lines :
orientationArray = orientation.split(',') #reading csv line as a list
selectOri = 0 #my tool to select the searched value in the list
gabor.ori = int(orientationArray[selectOri]) #select value as function of the "selectOri", in this case always the first one
continueroutine = True
while continueroutine:
if timer == 0.1: # This doesn't work but it shows you what is planned
selectOri = selectOri + 1 #update value
gabor.ori = int(orientationArray[selectOri]) #update value
win.flip()
I can't find a proper way to update in a desired time frame.
A neat way to do something every x frames is to use the modulo operation in combination with a loop containin win.flip(). So if you want to do something every 6 frames (100 ms on a 60 Hz monitor), just do this in every frame:
frame = 0 # the current frame number
while continueroutine:
if frame % 6 == 0: # % is modulo. Here every sixth frame
gabor.ori = int(orientationArray[selectOri + 1])
# Run this every iteration to synchronize the while-loop with the monitor's frames.
gabor.draw()
win.flip()
frame += 1
Related
Im trying to add coördinates to a set of addresses that are saved in an excel file using the google geocoder API. See code below:
for i, row in df.iterrows():
#below combines the address columns together in one variable, to push to the geocoder API.
apiAddress = str(df.at[i, 'adresse1']) + ',' + str(df.at[i, 'postnr']) + ',' + str(df.at[i, 'By'])
#below creates a dictionary with the API key and the address info, to push to the Geocoder API on each iteration
parameters = {
'key' : API_KEY,
'address' : apiAddress
}
#response from the API, based on the input url + the dictionary above.
response = requests.get(base_url, params = parameters).json()
#when you look at the response, it is given as a dictionary. with this command I access the geometry part of the dictionary.
geometry = response['results'][0]['geometry']
#within the geometry party of the dictionary given by the API, I access the lat and lng respectively.
lat = geometry['location']['lat']
lng = geometry['location']['lng']
#here I append the lat / lng to a new column in the dataframe for each iteration.
df.at[i, 'Geo_Lat_New'] = lat
df.at[i, 'Geo_Lng_New'] = lng
#printing the first 10 rows.
print(df.head(10))
the above code works perfectly fine for 20 addresses. But when I try to run it on the entire dataset of 90000 addresses; using iterrows() I get a IndexError:
File "C:\Users\...", line 29, in <module>
geometry = response['results'][0]['geometry']
IndexError: list index out of range
Using itertuples() instead, with:
for i, row in df.itertuples():
I get a ValueError:
File "C:\Users\...", line 22, in <module>
for i, row in df.itertuples():
ValueError: too many values to unpack (expected 2)
when I use:
for i in df.itertuples():
I get a complicated KeyError. That is to long to put here.
Any suggestions on how to properly add coördinates for each address in the entire dataframe?
Update, in the end I found out what the issue was. The google geocoding API only handles 50 request per second. Therefore I used to following code to take a 1 second break after every 49 requests:
if count == 49:
print('Taking a 1 second break, total count is:', total_count)
time.sleep(1)
count = 0
Where count keeps count of the number of loops, as soon as it hits 49, the IF statement above is executed, taking a 1 second break and resetting the count back to zero.
Although you have already found the error - Google API limits the amount of requests that can be done - it isn't usually good practice to use for with pandas. Therefore, I would re write your code to take advantage of pd.DataFrame.apply.
def get_geometry(row: pd.Series, API_KEY: str, base_url: str, tries: int = 0):
apiAddress = ",".join(row["adresse1"], row["postnr"], row["By"])
parameters = {"key": API_KEY, "address": apiAddress}
try:
response = requests.get(base_url, params = parameters).json()
geometry = response["results"][0]["geometry"]
except IndexError: # reach limit
# sleep to make the next 50 requests, but
# beware that consistently reaching limits could
# further limit sending requests.
# this is why you might want to keep track of how
# many tries you have already done, as to stop the process
# if a threshold has been met
if tries > 3: # tries > arbitrary threshold
raise
time.sleep(1)
return get_geometry(row, API_KEY, base_url, tries + 1)
else:
geometry = response["results"][0]["geometry"]
return geometry["location"]["lat"], geometry["location"]["lng"]
# pass kwargs to apply function and iterate over every row
lat_lon = df.apply(get_geometry, API_KEY = API_KEY, base_url = base_url, axis = 1)
df["Geo_Lat_New"] = lat_lon.apply(lambda latlon: latlon[0])
df["Geo_Lng_New"] = lat_lon.apply(lambda latlon: latlon[1])
Python newbie here. Here's a simplified example of my problem. I have 2 pandas dataframes.
One dataframe lightbulb_df has data on whether a light is on or off and looks something like this:
Light_Time
Light On?
5790.76
0
5790.76
0
5790.771
1
5790.779
1
5790.779
1
5790.782
0
5790.783
1
5790.783
1
5790.784
0
Where the time is in seconds since start of day and 1 is the lightbulb is on, 0 means the lightbulb is off.
The second dataframe sensor_df shows whether or not a sensor detected the lightbulb and has different time values and rates.
Sensor_Time
Sensor Detect?
5790.8
0
5790.9
0
5791.0
1
5791.1
1
5791.2
1
5791.3
0
Both dataframes are very large with 100,000s of rows. The lightbulb will turn on for a few minutes and then turn off, then back on, etc.
Using the .diff function, I was able to compare each row to its predecessor and depending on whether the result was 1 or -1 create a truth table with simplified on and off times and append it to lightbulb_df.
# use .diff() to compare each row to the last row
lightbulb_df['light_diff'] = lightbulb_df['Light On?'].diff()
# the light on start times are when
#.diff is less than 0 (0 - 1 = -1)
light_start = lightbulb_df.loc[lightbulb_df['light_diff'] < 0]
# the light off start times (first times when light turns off)
# are when .diff is greater than 0 (1 - 0 = 1)
light_off = lightbulb_df.loc[lightbulb_df['light_diff'] > 0]
# and then I can concatenate them to have
# a single changed state df that only captures when the lightbulb changes
lightbulb_changes = pd.concat((light_start, light_off)).sort_values(by=['Light_Time'])
So I end up with a dataframe of on start times, a dataframe of off start times, and a change state dataframe that looks like this.
Light_Time
Light On?
light_diff
5790.771
1
1
5790.782
0
-1
5790.783
1
1
5790.784
0
-1
Now my goal is to search the sensor_df dataframe during each of the changed state times (above 5790.771 to 5790.782 and 5790.783 to 5790.784) by 1 second intervals to see whether or not the sensor detected the lightbulb. So I want to end up with the number of seconds the lightbulb was on and the number of seconds the sensor detected the lightbulb for each of the many light on periods in the change state dataframe. I'm trying to get % correctly detected.
Whenever I try to plan this out, I end up using lots of nested for loops or while loops which I know will be really slow with 100,000s of rows of data. I thought about using the .cut function to divide up the dataframe into 1 second intervals. I made a for loop to cycle through each of the times in the changed state dataframe and then nested a while loop inside to loop through 1 second intervals but that seems like it would be really slow.
I know python has a lot of built in functions that could help but I'm having trouble knowing what to google to find the right one.
Any advice would be appreciated.
I am trying to get my head around the Pandas module and started learning about the Series data structure.
I have created the following Series in Spyder :-
songs = pd.Series(data = [145,142,38,13], name = "Count")
I can obtain information about the Series index using the code:-
songs.index
The output of the above code is as follows:-
My question is where it states Start = 0 and Stop = 4, what are these referring to?
I have interpreted start = 0 as the first element in the Series is in row 0.
But i am not sure what Stop value refers to as there are no elements in row 4 of the Series?
Can some one explain?
Thank you.
This concept as already explained adequately in the comments (indexing is at minus one the count of items) is prevalent in many places.
For instance, take the list data structure-
z = songs.to_list()
[145, 142, 38, 13]
len(z)
4 # length is four
# however indexing stops at i-1 position 'i' being the length/count of items in the list.
z[4] # this will raise an IndexError
# you will have to start at index 0 going till only index 3 (i.e. 4 items)
z[0], z[1], z[2], z[-1] # notice how -1 can be used to directly access the last element
I need to write a function below that can compute the moving average of time series using a sliding window over an array. This function should take an array of date strings (say arr_date), an array of numbers (say arr_record), and a sliding window (default value 50). It should:
Return a list of dictionaries for all windows.
Each dictionary should include the date, average value, min, max, standard deviation at each window.
Able to handle missing data in time series by replacing missing data with the most recent available data.
(b) Download SPY daily data (Dec. 31, 2017 to Dec. 31, 2018) from Yahoo! as your test data in a .csv file. Read reading .csv file example and write a test programming for calling your function.
Does anyone have any thoughts? Extremely new to python and struggling.
So something following this logic should probably be a good starting point. Hope this is a helpful start, and welcome to the cs community.
def sliding_window( dates, numbers, sliding_window_value):
# list of dictionaries
return_dicts =[{}]
# if window size is greater than length of dates, there's only one window
if sliding_window_value >= len(dates):
return_dicts += [create_window(dates, numbers)]
return return_dicts
# gather all our windows into one list
for i in range (0, len(dates) - sliding_window_value ):
# get our window subsets
dates_subset = dates[i:(sliding_window_value+1)]
numbers_subset = numbers[i:(sliding_window_value+1)]
# get our window stats dictionary
window_stats = create_window(dates_subset,numbers_subset)
# add these stats to our return list
return_dicts += [window_stats]
return return_dicts
def create_window(dates_subset, numbers_subset):
window_min = 1000000 # some high minimum to start
window_max = -1000000 # some low maximuim to start
window_total = 0
for i in range ( 0, len(dates_subset)):
# calculate total
window_total += numbers_subset[i]
# calculate max
if numbers_subset[i] > window_max:
window_max = numbers_subset[i]
# calculate min
if numbers_subset[i] < window_min:
window_min = numbers_subset[i]
# other calculations....
return_dict = {
"min" : window_min,
"max" : window_max,
"average" : window_total / len(dates_subset),
# other calculations....
}
return return_dict
Good luck bud, the work is worth it.
I'm developing a financial application in which I need to display data in a chart with a logarithmic scale on the Y axis. Everything works fine except for the intervals. With the following:
chart.ChartAreas(0).AxisY.IsLogarithmic = True
chart.ChartAreas(0).AxisY.LogarithmBase = 10
chart.ChartAreas(0).AxisY.Interval = 1
chart.ChartAreas(0).AxisY.Minimum = CalcMinYVal(minYVal)
I get the CalcMinYVal multiplied by 10^0,10^1,10^2,10^3 and so on for the Y-axis values.
I would like to have the Y axis values increased by 1. How can I have the interval be REALLY 1?
You can enable the MinorGrid property
chart.ChartAreas(0).AxisY.MinorGrid = True
to show the horizontal lines in between the powers of 10 like shown below.
But there is a limitation in showing the value for each subdivision. They can only appear in fixed intervals by using the Interval property of the LabelStyle.
For example to show 10 subdivisions, you can set:
Chart.ChartAreas(0).AxisY.LabelStyle.Interval = 0.1
The number of the horizontal lines of the MinorGrid can be controlled by using its Interval propery:
Chart.ChartAreas(0).AxisY.MinorGrid.Interval = 1
and the values of the labels can be rounded by using the format property:
Chart.ChartAreas(0).AxisY.LabelStyle.Format = "{0.0}"