I have MATLAB set to record three webcams at the same time. I want to capture and save each feed to a file and automatically increment it the file name, it will be replaced by experiment_0001.avi, followed by experiment_0002.avi, etc.
My code looks like this at the moment
set(vid1,'LoggingMode','disk');
set(vid2,'LoggingMode','disk');
avi1 = VideoWriter('X:\ABC\Data Collection\Presentations\Correct\ExperimentA_002.AVI');
avi2 = VideoWriter('X:\ABC\Data Collection\Presentations\Correct\ExperimentB_002.AVI');
set(vid1,'DiskLogger',avi1);
set(vid2,'DiskLogger',avi2);
and I am incrementing the 002 each time.
Any thoughts on how to implement this efficiently?
Thanks.
dont forget matlab has some roots to C programming language. That means things like sprintf will work
so since you are printing out an integer value zero padded to 3 spaces you would need something like this sprintf('%03d',n) then % means there is a value to print that isn't text. 0 means zero pad on the left, 3 means pad to 3 digits, d means the number itself is an integer
just use sprintf in place of a string. the s means String print formatted. so it will output a string. here is an idea of what you might do
set(vid1,'LoggingMode','disk');
set(vid2,'LoggingMode','disk');
for (n=1:2:max_num_captures)
avi1 = VideoWriter(sprintf('X:\ABC\Data Collection\Presentations\Correct\ExperimentA_%03d.AVI',n));
avi2 = VideoWriter(sprintf('X:\ABC\Data Collection\Presentations\Correct\ExperimentB_002.AVI',n));
set(vid1,'DiskLogger',avi1);
set(vid2,'DiskLogger',avi2);
end
Related
I have some code
::redo::
io.write("input: ")
var = io.read("*n")
if var then
if var > 5 and var < 10 then io.write("yes\n") goto redo
else io.write("invalid\n") goto redo end
else io.write("invalid\n") goto redo end
that is supposed to check a numeric input value and return if it's within a certain range. If it isn't a numeric value, it's supposed to "redo" the script and ask for input again. The issue is that whenever it takes an input that isn't a number it repeats io.write("input: ") and io.write("invalid\n") unceasingly meaning it's skipping the var = io.read("*n") line. Is there a special meaning or quirk to io.read("*n") that keeps it from reevaluating? The code seems to work if replaced with io.read()
When you call io.read('*n') and it doesn't find a number, it doesn't use up the input, and any calls to io.read('*n') will read the same input over and over. You need to eat up the input and discard it by calling io.read('*l'). That will let you read new input with io.read('*n').
Another method would be to read a line with io.read('*l'), extract a number from it with string.match and convert it to a number with tonumber. Then you don't have to read the same input twice, but you'd have to decide what types of number notation you want to match. (io.read('*n') accepts various types of numbers, including hexadecimal and scientific notation.)
I am wondering how to make something where if X=5 and Y=2, then have it output something like
Hello 2 World 5.
In Java I would do
String a = "Hello " + Y + " World " + X;
System.out.println(a);
So how would I do that in TI-BASIC?
You have two issues to work out, concatenating strings and converting integers to a string representation.
String concatenation is very straightforward and utilizes the + operator. In your example:
"Hello " + "World"
Will yield the string "Hello World'.
Converting numbers to strings is not as easy in TI-BASIC, but a method for doing so compatible with the TI-83+/84+ series is available here. The following code and explanation are quoted from the linked page:
:"?
:For(X,1,1+log(N
:sub("0123456789",ipart(10fpart(N10^(-X)))+1,1)+Ans
:End
:sub(Ans,1,length(Ans)-1?Str1
With our number stored in N, we loop through each digit of N and store
the numeric character to our string that is at the matching position
in our substring. You access the individual digit in the number by
using iPart(10fPart(A/10^(X, and then locate where it is in the string
"0123456789". The reason you need to add 1 is so that it works with
the 0 digit.
In order to construct a string with all of the digits of the number, we first create a dummy string. This is what the "? is used
for. Each time through the For( loop, we concatenate the string from
before (which is still stored in the Ans variable) to the next numeric
character that is found in N. Using Ans allows us to not have to use
another string variable, since Ans can act like a string and it gets
updated accordingly, and Ans is also faster than a string variable.
By the time we are done with the For( loop, all of our numeric characters are put together in Ans. However, because we stored a dummy
character to the string initially, we now need to remove it, which we
do by getting the substring from the first character to the second to
last character of the string. Finally, we store the string to a more
permanent variable (in this case, Str1) for future use.
Once converted to a string, you can simply use the + operator to concatenate your string literals with the converted number strings.
You should also take a look at a similar Stack Overflow question which addresses a similar issue.
For this issue you can use the toString( function which was introduced in version 5.2.0. This function translates a number to a string which you can use to display numbers and strings together easily. It would end up like this:
Disp "Hello "+toString(Y)+" World "+toString(X)
If you know the length of "Hello" and "World," then you can simply use Output() because Disp creates a new line after every statement.
I have a string called indicators, that the original developer of this application used to store single characters to indicate certain components of a model. I need to change the 7th character in the string, which I tried to do with the following code:
indicators[6] = "R"
The problem, I discovered quickly, was that the string is not always 7 characters long. For example, I have one set of values with U 2, that I need to convert to U 2 R (adding an additional space after the 2). Is there an easy way to force character count with Ruby?
use String.ljust(integer, padstr=' ')
If integer is greater than the length of [the receiver], returns a new String of
length integer with [the return value] left justified and padded with padstr;
otherwise, returns [an unmodified version of the receiver].
indicators = indicators.ljust(7)
indicators[6] = "R"
Dim str as String
str = "30 40 50 60"
I want to count the number of substrings.
Expected Output: 4
(because there are 4 total values: 30, 40, 50, 60)
How can I accomplish this in VB6?
You could try this:
arrStr = Split(str, " ")
strCnt = UBound(arrStr) + 1
msgBox strCnt
Of course, if you've got Option Explicit set (which you should..) then declare the variables above first..
Your request doesn't make any sense. A string is a sequence of text. The fact that that sequence of text contains numbers separated by spaces is quite irrelevant. Your string looks like this:
30 40 50 60
There are not 4 separate values, there is only one value, shown above—a single string.
You could also view the string as containing 11 individual characters, so it could be argued that the "count" of the string would be 11, but this doesn't get you any further towards your goal.
In order to get the result that you expect, you need to split the string into multiple strings at each space, producing 4 separate strings, each containing a 2-digit numeric value.
Of course, the real question is why you're storing this value in a string in the first place. If they're numeric values, you should store them in an array (for example, an array of Integers). Then you can easily obtain the number of elements in the array using the LBound() and UBound() functions.
I agree with everything Cody stated.
If you really wanted to you could loop through the string character by character and count the number of times you find your delimiter. In your example, it is space delimited, so you would simply count the number of spaces and add 1, but as Cody stated, those are not separate values..
Are you trying to parse text here or what? Regardless, I think what you really need to do is store your data into an array. Make your life easier, not more difficult.
Is it possible to use variables in both fields of the gsub method ?
I'm trying to get this piece of code work :
$I = 0
def random_image
$I.to_s
random = rand(1).to_s
logo = File.read('logo-standart.txt')
logo_aleatoire = logo.gsub(/#{$I}/, random)
File.open('logo-standart.txt', "w") {|file| File.puts logo_aleatoire}
$I.to_i
$I += 1
end
Thanks in advance !
filecontents = File.read('logo-standart.txt')
filecontents.gsub!(/\d+/){rand(100)}
File.open("logo-standart.txt","w"){|f| f << filecontents }
The magic line is the second line.
The gsub! function modifies the string in-place, unlike the gsub function, which would return a new string and leave the first string unmodified.
The single parameter that I passed to gsub! is the pattern to match. Here, the goal is to match any string of one or more digits -- this is the number that you're going to replace. There's no need to loop through all of the possible numbers running gsub on each one. You can even match numbers as high as a googol (or higher) without your program taking longer and longer to run.
The block that gsub! takes is evaluated each time the pattern matches to programmatically generate a replacement number. So each time, you get a different random number. This is different from the more usual form of gsub! that takes two parameters -- there the parameter is evaluated once before any pattern matching occurs, and all matches are replaced by the same string.
Note that the way this is structured, you get a new random number for each match. So if the number 307 appears twice, it turns into two different random numbers.
If you wanted to map 307 to the same random number each time, you could do the following:
filecontents = File.read('logo-standart.txt')
randomnumbers = Hash.new{|h,k| h[k]=rand(100)}
filecontents.gsub!(/\d+/){|match| randomnumbers[match]}
File.open("logo-standart.txt","w"){|f| f << filecontents }
Here, randomnumbers is a hash that lets you look up the numbers and find what random number they correspond to. The block passed when constructing the hash tells the hash what to do when it finds a number that it hasn't seen before -- in this case, generate a new random number, and remember what that random number the mapping. So gsub!'s block just asks the hash to map numbers for it, and randomnumbers takes care of generating a new random number when you encounter a new number from the original file.