how to add zeros in fronts of any number in matrix

dten = datenum([1998 1 1 ;2002 12 31]);

[M] = datevec(dten(1):dten(2));

years = M(:,1);

months = M(:,2);

days = M(:,3);

i want to add zeros in front of 1, 2, 3, 4, 5, 6, 7, 8, 9 like this 01, 02, 03, 04, 05, 06, 07, 08, 09 in months and days matrix. how will do this. please help me. thank you in advance.

Answer 1

[Konstantinos Sofos]

Asking for this probably you do not want anymore your years, months, days vectors to be numbers but chars. Because you know from basic maths that '01' doesn't exist as type of number.

myCellMonth =  cellfun(@(x) num2str(x),num2cell(months),'UniformOutput', false);

idx = cellfun(@(x) numel(x),myCellMonth);

idx = idx==1; % we want to add a leading '0' only in front of 1,2,3,...9

myCellMonth(idx) = cellfun(@(x) strcat('0', x),myCellMonth(idx),'UniformOutput', false)

In the same logic you could reform days and years

Regards

[Konstantinos Sofos]

After your comment you could use the above as

filename1 = ['3B42_daily.',myCellYears{i},'.',myCellMonth{i},'.',myCellDay{i},'.7.SUB.nc']

And as an example if i = 1

filename1 = ['3B42_daily.',myCellyears{1},'.',myCellMonth{1},'.',myCelldays{1},'.7.SUB.nc']

will give you as result

filename1 =

3B42_daily.1998.01.01.7.SUB.nc

[devendra]

thank you so much Konstantinos Sofos this is helping alot but can we remove ' ' (inverted commas) from this because this is giving this type of output.

'01'

'01'

'01'

[Konstantinos Sofos]

dten = datenum([1998 1 1 ;2002 12 31]);
[M] = datevec(dten(1):dten(2));
years = M(:,1);
months = M(:,2);
days = M(:,3);

%DAYS

myCellDay =  cellfun(@(x) num2str(x),num2cell(days),'UniformOutput', false);
idx = cellfun(@(x) numel(x),myCellDay);
idx = idx==1;
myCellDay(idx) = cellfun(@(x) strcat('0', x),myCellDay(idx),'UniformOutput', false);

%MONTHS

myCellMonth =  cellfun(@(x) num2str(x),num2cell(months),'UniformOutput', false);
idx = cellfun(@(x) numel(x),myCellMonth);
idx = idx==1; % we want to add a leading '0' only in front of 1,2,3,...9
myCellMonth(idx) = cellfun(@(x) strcat('0', x),myCellMonth(idx),'UniformOutput', false);

% YEARS

myCellYears =  cellfun(@(x) num2str(x),num2cell(years),'UniformOutput', false);
idx = cellfun(@(x) numel(x),myCellYears);
idx = idx==1;
myCellYears(idx) = cellfun(@(x) strcat('0', x),myCellYears(idx),'UniformOutput', false);

for i = 1:numel(M(:,1))
   filename = ['3B42_daily.',myCellYears{i},'.',myCellMonth{i},'.',myCellDay{i},'.7.SUB.nc'] 
end

[Konstantinos Sofos]

for the ' ' (inverted commas) use {} instead of () to read the context of a char cell array as i showed above. Hope that this helps.

[devendra]

thank you so much Konstantinos Sofos for helping me.

Answer 2

[Jan]

sprintf and also num2str can use the '%02d' format:

myCellMonth =  cellfun(@(x) num2str(x, '%02d'), num2cell(months),'UniformOutput', false);

This inserts a leading zero, when the number has less than 2 digits. Instead of preparing cell strings, you can use sprintf directly:

for i = 1:numel(M(:,1))
   filename = sprintf('3B42_daily.%04d.%02d.%02d.7.SUB.nc', year(i), month(i), day(i));
   ...
end