Change digits in strings
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Hello,
I have a problem. How I can change digits in string for example:
"A[12,12]*A[12,12]+A[9,12]*A[12,9]+A[5,2]*A[1,3]"
to have
"A[11,11]*A[11,11]+A[8,11]*A[11,8]+A[4,1]*A[0,]"
using regexprep ?
Best
采纳的回答
Guillaume
2016-5-10
You need to use a dynamic replacement string
str = '"A[12,12]*A[12,12]+A[9,12]*A[12,9]+A[5,2]*A[1,3]"';
regexprep(str, '\d+', '${num2str(str2double($0)-1)}')
8 个评论
Guillaume
2016-5-11
Mariusz's comment posted as an answer moved here:
Hello,
Thank you for your help.
I have one problem. For example:
Temp1 := 'A[1,1]*A[1,1]+A[1,2]'
Temp2 := 'A[1,1]*A[1,1]+A[1,2]'
How to split string by '='?. When I use regexp I have
' Temp1 ' [1x45 char] [1x45 char]
but I wont to have
' Temp1 ' [1x45 char] ' Temp1 ' [1x45 char]
Best
Guillaume
2016-5-11
Please use comments rather than starting a new answer.
I'm confused as to how this relates to the previous question? Do you still want to decrease the numbers in the string? If this is unrelated, you should accept my answer and start a new question.
Additionally, it's not clear what your input is. Is it a 2D char array? a cell array of strings? something else?
The output of regexp is totally dependent on what regular expression you use, so if you say that a regular expression does not work, please show that regular expression.
Mariusz
2016-5-12
Guillaume
2016-5-12
The output you get makes sense. regexp does not care about line ending characters, as far as it is concerned your input is a single string and you ask it to split it at the :=, so the second portion of the string is ' A[1,1]+b[1,1]; \nK[0,1] '. What you really want is to split the string at the := and at the newline:
STR = sprintf('%s\n%s\n%s\n%s\n', ...
'K[0,0] := A[1,1]+b[1,1]; ', ...
'K[0,1] := A[1,2]+b[1,2]; ', ...
'K[1,0] := A[2,1]+b[2,1]; ', ...
'K[1,1] := A[2,2]+b[2,2]; ')
regexp(STR, ':=|\n', 'split')
%or if you want to trim the strings at the same time
regexp(STR, '\s*(:=|\n)\s*', 'split')
Mariusz
2016-5-13
The original regular expression would match any continuous sequence of digits and decrease that sequence by 1. If you want restrictions on that, it's up to you to specify these restrictions in the regex. Your question is too open ended for me to know what these are. They could be:
- only match digits immediately following an opening square bracket or immediately preceding a closing square bracket:
regexprep(s, '(?<=\[)\d+|\d+(?=\])', '${num2str(str2double($0)-1)}')
- only match digits preceded or followed by anything but '.', which would restrict it to integers as long as you don't use e notation. One possible downside of this is that the digits can't be at the beginning or end of the string
regexprep(s, '(?<=[^.])\d+(?=[^.])', '${num2str(str2double($0)-1)}')
- something else
Note that it is difficult in regular expression to say to not match something
Mariusz
2016-5-23
arthur doroshev
2020-12-15
and if you want to get from
'A[12,12]*A[12,12]+A[9,12]*A[12,9]+A[5,2]*A[1,3]'
that
'A[1]*A[2]+A[3]*A[4]+A[5]*A[6]'
what to do then?
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