replacing text in a string using indexing

how could replace text by just using one line of code

e.g. a = 'qqqqqq' and I want to make q = 'qweqwe'

Answer 1

[Mathieu NOE]

I win the prize !

out = strrep('qqqqqq','qqqqq','qwe')

out =

    'qweqwe'

[Lin]

thanks !

but what if i want to make 'qqqqqqqqqq' to 'qweqweqweq'

sorry for the dumb question, still a rookie and have a hard beginning using matlab

[Mathieu NOE]

look at the doc for function strrep

strrep Find and replace substring.

MODIFIEDTEXT = strrep(ORIGTEXT,OLDSUBTEXT,NEWSUBTEXT) replaces all

occurrences of the text OLDSUBTEXT within text ORIGTEXT with the

text NEWSUBTEXT.

the trick here is to count how many times you want the pattern 'qwe' repeated in the output (modified) text

you last query request 3 time 'qwe' to make 'qweqweqweq' so we will take the input text ('qqqqqqqqqq') and remove 3 - 1 = 2 'q' from this character to create the subtext

here a liitle demo where I remove 0,1,2 times the q

out1 = strrep('qqqqqqqqqq' ,'qqqqqqqqqq' ,'qwe') % zero 'q' removed in subtext (compared to input text)

out2 = strrep('qqqqqqqqqq' ,'qqqqqqqqq' ,'qwe') % one 'q' removed in subtext

out3 = strrep('qqqqqqqqqq' ,'qqqqqqqq' ,'qwe') % two 'q' removed in subtext

out1 = 'qwe'

out2 = 'qweqwe'

out3 = 'qweqweqwe'

Answer 2

[Stephen23]

For overlapping matches use STRREP.

For non-overlapping matches use REGEXPREP:

regexprep('qqqqqq','qqq','qwe')

ans = 'qweqwe'

regexprep('qqqqqqqqq','qqq','qwe')

ans = 'qweqweqwe'