I'm getting a byte array like this one:
[60, 2, 0, 0, 0]
In the documentation there is written this:
uint16 -> heartBeatNum;
uint8 -> rawDataFilesNum;
uint8 -> alertNum
uint8 -> fallsNum
I will explain a little about the device so that you understand and then I ask my question.
The bluetooth device sends an object every minute that is called heartbeat. If this is the first time the object is to use the array looks like this:
After first minute:
[1, 0, 0, 0, 0]
After two minute:
[2, 0, 0, 0, 0]
After three minute:
[3, 0, 0, 0, 0]
After for minute:
[4, 0, 0, 0, 0]
...
Now there are more than 12 that have passed and the array is:
[60, 2, 0, 0, 0]
So I try to understand from the documentation the heartbeat count is the first 16 bytes. I can not figure out how to collect the 60's and the 2's to have the exact heartbeat number.
How does this function?
According to my calculation if I do 60 * 12 = 720
So I should have about 700
Can someone enlighten me how to gather the 16 bytes in int?
Related
It seems like a combination of collect(every:on:skipEmpty:discardWhenCompleted:) and collect(count:) in ReactiveSwift.
The resulting signal would send an event every n seconds if the count of accumulated values doesn't reach max count during each time interval. But if in a specific time interval, the count of values has reached max count, it will send immediately.
For example, timeInterval = 2s, maxCount = 2
interval 1: received two values [1, 2], forward them at end of interval 1
interval 2: received one value [3], forward them at end of interval 2
interval 3: received three values [5, 6, 7] ( 3 values > maxCount), forward [5, 6] immediately when 7 is received and 7 is regarded as received value in interval 4 (interval 3 stopped early)
Question is hard to grasp, but I will try.
If you want to batch emitted values by count and time, you can use bufferTimeout method. See documentation here https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Flux.html#bufferTimeout-int-java.time.Duration-
Some example:
void bufferTimeoutTry() throws InterruptedException {
Flux.interval(Duration.ofMillis(157))
.filter(time -> time > 20 && time < 38 || time % 5 == 0 || time % 17 == 0)
.bufferTimeout(5, Duration.ofSeconds(1))
.doOnNext(list -> {
// we will get list of items buffered in 1-second period of time, or at most 5 items.
})
.subscribe(System.out::println);
Thread.sleep(30000);
}
Output will be list of items. Flux.interval is generating sequential long number (i.e. 1, 2, 3, 4, 5, ...), it is filtered on second line of method (to get some non interval behavior) and than buffer-ed. After buffer, there is no long on stream, but it has changed to list of longs.
[0, 5]
[10, 15]
[17, 20, 21, 22, 23]
[24, 25, 26, 27, 28]
[29, 30, 31, 32, 33]
[34, 35, 36, 37, 40]
[45, 50, 51]
[55, 60]
[65, 68, 70]
[75, 80]
[85, 90]
[95, 100]
[102, 105]
[110, 115]
[119, 120, 125]
[130, 135, 136]
[140, 145]
[150, 153, 155]
[160, 165]
[170, 175]
[180, 185]
Is this what you want?
Hi I trying to send 9 bytes to specific characteristic, where first byte is 0x05 , i.e 5 ,and next 8 bytes as epoch in seconds,
I tried this,
List<int> timeDataForBLEWrite = [0x5, 0, 0, 0, 0, 0, 0, 0, 0 ]; // here 0 will be replaced by 8 bytes of epoch
to get epoch in seconds, I tried this,
int timestampEpochInSeconds = DateTime.now().millisecondsSinceEpoch ~/ 1000; // 1623331779
to convert epoch into bytes I have tried this,
List<int> bytes = utf8.encode(timestampEpochInSeconds.toString());
but here I am getting 10 bytes because timestampEpochInSeconds is 1623331779 // 10 digits
print(bytes); // [49, 54, 50, 51, 51, 51, 49, 55, 55, 57]
how can I get 8 integers from the seconds epoch so that I can send total 9 bytes to the characteristic. like below,
characteristic.write(timeDataForBLEWrite);
I am assuming that you don't want the string in bytes but the values in bytes.
Most data in Bluetooth is in Little Endian so I have made that assumption about the timestamp as bytes.
I did the following as an example on DartPad:
import 'dart:typed_data';
List<int> epoch() {
var timestamp = DateTime.now().millisecondsSinceEpoch ~/ 1000;
var sendValueBytes = ByteData(9);
sendValueBytes.setUint8(0, 5);
// setUint64 not implemented on some systems so use setUint32 in
// those cases. Leading zeros to pad to equal 64 bit.
// Epoch as 32-bit good until 2038 Jan 19 # 03:14:07
try {
sendValueBytes.setUint64(1, timestamp.toInt(), Endian.little);
} on UnsupportedError {
sendValueBytes.setUint32(1, timestamp.toInt(), Endian.little);
}
return sendValueBytes.buffer.asUint8List();
}
void main() {
print('Epoch Bytes (plus 0x05): ${epoch()}');
}
Which gave the following output:
Epoch Bytes (plus 0x05): [5, 167, 60, 194, 96, 0, 0, 0, 0]
I have a dataset that resembles the following:
site_id, species
1, spp1
2, spp1
2, spp2
2, spp3
3, spp2
3, spp3
4, spp1
4, spp2
I want to create a table like this:
site_id, spp1, spp2, spp3, spp4
1, 1, 0, 0, 0
2, 1, 1, 1, 0
3, 0, 1, 1, 0
4, 1, 1, 0, 0
This question was asked here, however the issue I face is that my list of species is significantly greater and so creating a massive query listing each species manually would take a significant amount of time. I would therefore like a solution that does not require this and could instead read from the existing species list.
In addition, when playing with that query, the count() function would keep adding so I would end up with values greater than 1 where multiples of the same species were present in a site_id. Ideally I want a binary 1 or 0 output.
Say I have an array of Ints and all elements equal zero. It'd look something like this:
let arr: [Int] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
There are 11 elements in this array in total. I want three of the elements in this array to be the number one. I want these one values to be distributed evenly throughout the array so that it looks something like this:
[0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0]
I want to be able to add however many one's and distribute them evenly (or as close to evenly as possible) no matter how many total elements there are. How could I do this?
Note: For anyone wondering why I need this, I have a collection of strings that when joined together make up a large body of text. Think of the zeroes as the pieces of text and think of the ones as advertisements I am adding in between the text. I wanted to distribute these ads as evenly as possible. I figured this would be a simple way of expressing what I needed.
Maybe you can try this.
var arr: [Int] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
let distribution = arr.count / 3 // 3 is the number of 1s
for (index, value) in arr.enumerated() {
arr[index] = (index + 1) % distribution == 0 ? 1 : value
}
print(arr) // [0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0]
Assuming that the value distribution > 1
I'm using textscan to import data. I can get to it successfully import properly formatted data. I can't get it to properly handle data that isn't properly formatted. Below is the format of the data.
JeB2021Da 12-13 and stuff, 1, 1, 0, 1, 0, 1, 1, 1, 3, 1, 99, 0, 0, 0,
JoB2021Ha 12-13 and stuff, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 99, 2, 1, 0,
JoP2021Co 12-13 and stuff, not enough samples
MaA2021Be 12-13 and stuff, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 99, 1, 0, 0,
MaA2021Ma 12-13 and stuff, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 99, 1, 0, 0,
How would I handle the data that is, not enough samples? Because currently the data structures don't line up. The data structures that are being produced are 17 x 1 and 16 x 14. I'd like to import the string as it is in the data. So not enough samples would be imported. Below is the code that I'm using.
fid = fopen('./file.txt','r');
fmt = ['%s %d %d %d %d %d %d %d %d %d %d %d %d %d %d'];
d = textscan(fid, fmt, 'CollectOutput', 1,'Delimiter',',','headerLines', 1, 'EmptyValue', 0);
I'm trying to handle it with the EmptyValue flag but it's not working. Any help is greatly appreciated.
I am not sure what exactly you mean by I'd like to import the string as it is in the data, or more exactly where you would like to have that string stored.
But about just reading your data as a whole you can use the 'TreatAsEmpty' argument:
d = textscan(fid, fmt, 'CollectOutput', 1,'Delimiter',',','headerLines', 1,'TreatAsEmpty','not enough samples');
Then you can modify the input further by looking for the rows in the imported data array that solely consist of zeros.