for-loop

问题 I have a large dataset of samples with descriptors of whether the sample is viable - it looks (kind of) like this, where 'desc' is the description column and 'blank' indicates the sample is not viable: desc x y z 1 blank 4.529976 5.297952 5.581013 2 blank 5.906855 4.557389 4.901660 3 sample 4.322014 4.798248 4.995959 4 sample 3.997565 5.975604 7.160871 5 blank 4.898922 7.666193 5.551385 6 blank 5.667884 5.195825 5.232072 7 blank 5.524773 6.726074 4.767475 8 sample 4.382937 5.926217 5.203737 9

问题 I am trying to find way to break / exit from FOR loop, if there are any error occured. Below is content of batch file. @echo on set myfile=D:\sample.txt FOR /F "tokens=1,2 delims=," %%i in (%myfile%) do call :process "%%i" :process set recfile=%1% echo %recfile% echo "Step in Test1" echo %errorlevel% pause; exit /B 0 If %errorlevel% NEQ 0 goto :fail1 :fail1 echo "Step in fail1" pause; exit /B 9993 :EOF Sample.txt has multiple records. If there are any error occured then I am expecting to exit

问题 In MATLAB the following for loop: for i = [1:100]' %'// Do something, such as disp(i) end isn't apparently really implemented by iteration, rather i becomes the matrix [1 2 3 ... 100] and the "loop" is only executed once on this matrix i . You can verify this by printing the value of i or other tracking information. Only a single pass is made through the loop. Is it possible to force MATLAB to do genuine looping? The reason I ask is that the above approach is fine for many cases but much more

问题 In MATLAB the following for loop: for i = [1:100]' %'// Do something, such as disp(i) end isn't apparently really implemented by iteration, rather i becomes the matrix [1 2 3 ... 100] and the "loop" is only executed once on this matrix i . You can verify this by printing the value of i or other tracking information. Only a single pass is made through the loop. Is it possible to force MATLAB to do genuine looping? The reason I ask is that the above approach is fine for many cases but much more

问题 Iam trying to compare each string or int in array with another array then print the results according to whether the string exists or not in the other array: Below is the whole code: I get error in the for loops when trying to comparing two values using .equals(not sure if its right method,,... I am new to this) Please help! public class comparer { public void compare (){ ArrayList NameofFileinDir = new ArrayList (); ArrayList Stocks = new ArrayList(); // populate array with files names in

问题 The new ranged-for in C++11 will be very concise and useful, of course. As far as I understand how it works, it looks up the "containers" begin and end by trying *Argument-Depending-Lookup" (ADT). But another addition is that all the containers now have cbegin() and cend() to get the const_iterators for the container. I am a bit confused, on the one hand I guess I should use cbegin() if I do not want to modify the container, on the other hand I have to add an additional const inside the

问题 The new ranged-for in C++11 will be very concise and useful, of course. As far as I understand how it works, it looks up the "containers" begin and end by trying *Argument-Depending-Lookup" (ADT). But another addition is that all the containers now have cbegin() and cend() to get the const_iterators for the container. I am a bit confused, on the one hand I guess I should use cbegin() if I do not want to modify the container, on the other hand I have to add an additional const inside the

问题 import java.util.ArrayList; import java.util.List; public class IterationBenchmark { public static void main(String args[]){ List<String> persons = new ArrayList<String>(); persons.add("AAA"); persons.add("BBB"); persons.add("CCC"); persons.add("DDD"); long timeMillis = System.currentTimeMillis(); for(String person : persons) System.out.println(person); System.out.println("Time taken for legacy for loop : "+ (System.currentTimeMillis() - timeMillis)); timeMillis = System.currentTimeMillis();

问题 Let's say I write a for loop that will output all the numbers 1 to x: x=4 for number in xrange(1,x+1): print number, #Output: 1 2 3 4 Now, putting that same for loop into a function: def counter(x): for number in xrange(1,x+1): return number print counter(4) #Output: 1 Why do I only obtain one value when I put the for-loop into a function? I have been evading this problem by appending all the results of the for-loop to a list, and then returning the list. Why does the for loop append all the

问题 for iteration in range(len(list) - 1): index = iteration +1 #This is the line which has no effect on the inner loop for index in range(len(list)): if list[iteration] > list[index]: newmin = list[index] newminindex = index if iteration != newminindex : swapnumbers(list,iteration, newminindex) The above is a code snippet I wrote for selection sort algorithm. However I see the inner loop start counter always starting from 0. Request for expert comment. 回答1: The for index in range(len(list)) loop