matlab mkdir gives error

I have a folder named results. I want to create a folder with name datetime in it. I use mkdir but I get error.

t = datetime('now');
  folder = ['../results/', datestr(t)];
  mkdir(folder);

Error using mkdir The filename, directory name, or volume label syntax is incorrect.

Answer 1

[Walter Roberson]

The colon separating the hours and minutes is a reserved character in NTFS filesystems.

https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#naming_conventions

[Walter Roberson]

t = datestr(now, 'dd-mmm-yyyy HH-MM-SS');
folder = fullfile('C:\Users\H\Documents\MATLAB\EntropyRateSuperpixel-master\results, t);
mkdir(folder);

Answer 2

[Image Analyst]

Look at this:

>> datestr(now)
ans =
    '13-Jul-2017 23:16:35'

You see those colons in there? The operating system uses those after drive letters, which doesn't make sense for that string. You can use strrep() to replace the colons with something else.

folder = strrep(folder, ':', '_');

Or just delete them,

folder = strrep(folder, ':', '');

or extract out the date only and not the time.

folder = folder(1:11);

Answer 3

[RuiQi]

The colons were giving an issue. This worked.

t = datetime('now');
t = datestr(t);
t = strrep(t,':','-')
folder = ['C:\Users\H\Documents\MATLAB\EntropyRateSuperpixel-master\results\', t];
mkdir(folder);