slice

In C, is there any built-in array slicing mechanism? Like in Matlab for example, A(1:4) would produce = 1 1 1 1 How can I achieve this in C? I tried looking, but the closest I could find is this: http://cboard.cprogramming.com/c-programming/95772-how-do-array-subsets.html subsetArray = &bigArray[someIndex] But this does not exactly return the sliced array, instead pointer to the first element of the sliced array... Many thanks Doing that in std C is not possible. You have to do it yourself. If you have a string, you can use string.h library who takes care of that, but for integers there's no

This question already has an answer here: Use slice notation with collections.deque 6 answers I've changed some code that used a list to using a deque. I can no longer slice into it, as I get the error: TypeError: sequence index must be integer, not 'slice' Here's a REPL that shows the problem. >>> import collections >>> d = collections.deque() >>> for i in range(3): ... d.append(i) ... >>> d deque([0, 1, 2]) >>> d[2:] Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: sequence index must be integer, not 'slice' So, is there a workaround to support slicing into

I am trying to reimplement in python an IDL function: http://star.pst.qub.ac.uk/idl/REBIN.html which downsizes by an integer factor a 2d array by averaging. For example: >>> a=np.arange(24).reshape((4,6)) >>> a array([[ 0, 1, 2, 3, 4, 5], [ 6, 7, 8, 9, 10, 11], [12, 13, 14, 15, 16, 17], [18, 19, 20, 21, 22, 23]]) I would like to resize it to (2,3) by taking the mean of the relevant samples, the expected output would be: >>> b = rebin(a, (2, 3)) >>> b array([[ 3.5, 5.5, 7.5], [ 15.5, 17.5, 19.5]]) i.e. b[0,0] = np.mean(a[:2,:2]), b[0,1] = np.mean(a[:2,2:4]) and so on. I believe I should reshape

I have switched from R to pandas. I routinely get SettingWithCopyWarnings, when I do something like df_a = pd.DataFrame({'col1': [1,2,3,4]}) # Filtering step, which may or may not return a view df_b = df_a[df_a['col1'] > 1] # Add a new column to df_b df_b['new_col'] = 2 * df_b['col1'] # SettingWithCopyWarning!! I think I understand the problem, though I'll gladly learn what I got wrong. In the given example, it is undefined whether df_b is a view on df_a or not. Thus, the effect of assigning to df_b is unclear: does it affect df_a ? The problem can be solved by explicitly making a copy when

Passing arrays (dynamic or static) to methods/procedures/functions with open array parameters , declaration can look like this: procedure WorkWithArray( const anArray : array of Integer); (* or procedure WorkWithArray( var anArray : array of Integer); *) var i : Integer; begin for i := Low(anArray) to High(anArray) do begin // Do something with the "open array" anArray WriteLn(anArray[i]); end; end; ... var staticArray : array[0..2] of Integer; dynArray : array of integer; dynArrayG : TArray<Integer>; begin SetLength(dynArray,10); SetLength(dynArrayG,10); WorkWithArray(staticArray); // Using a

Trying to learn Go from the tutorial right now, and have a pretty basic question: func main() { a := make([]int, 5) // [0,0,0,0,0] len=5 cap=5 b := make([]int, 0, 5) // [] len=0 cap=5 c := b[:2] // [0,0] len=2 cap=5 d := c[2:5] // [0,0,0] len=3 cap=3 } Why does c look like [0,0] and have length 2? b was not originally zero'ed hence it being [] . So does setting c to b[:2] zero out the first two elements? Also, why is the capacity of d 3? Very confused. Thanks in advance. All your variables have a slice type . Slices have a backing array . In Go you can't access uninitialized variables. If you