How to use shell regex command to split input line into tokens of decimals and operators?-CodePudding

How to use grep/sed/awk to achieve this:

Input: a statement of decimals and numeric operators and parentheses, can have tab and spaces in between:

2   5* 61.2 -(32.5 7)/ 8

Output: a string, containing each token(either a decimal or an operator or parentheses), seperated by a single comma:

2, ,5,*,61.2,-,(,32.5, ,7,),/,8

Could regular expression grep/sed/awk achieve this?

CodePudding user response：

echo '2   5* 61.2 -(32.5 7)/ 8' |
sed -Ee 's:[0-9] (\.[0-9] )?|[- */()]:&,:g' \
    -e  's/[[:blank:]] //g' \
    -e  's/,$//'

Gives:

2, ,5,*,61.2,-,(,32.5, ,7,),/,8

Global replace on a regex matching integers, decimal numbers, or one of the six characters - */(). Then remove tabs and spaces, and trailing comma.

CodePudding user response：

You may use this sed solution:

s='2   5* 61.2 -(32.5 7)/ 8'
sed -E 's~[[:blank:]]*([0-9] (\.[0-9] )?|[ /*()-])[[:blank:]]*~\1,~g; s/,$//' <<< "$s"
2, ,5,*,61.2,-,(,32.5, ,7,),/,8

CodePudding user response：

$ sed -E 's/ |\t//g;s/([-\ \*\/)(])/,\1,/g;s/,,*/,/g' <<<"2   5* 61.2 -(32.5 7)/ 8"
2, ,5,*,61.2,-,(,32.5, ,7,),/,8