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Import and Export Wolfram Language

Importing a number after a string?

S G

Posted 4 years ago

Hi, How to copy a real number after a string in a text file. This number can be in any form (integer /decimal /exponential). For example aaaa bbb (xyz / cc.dd ee) : = 3.456e2 or aaaa bbb (xyz / cc.dd ee) : = 345.6 or aaaa bbb (xyz / cc.dd ee) : = 345 I need a function, which can copy the numerical value after "aaaa bbb (xyz / cc.dd ee) : =" irrespective of its form. Thanks for the help.

POSTED BY: S G

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Hans Milton

Posted 4 years ago

Basically the same as Rohits last post, but without need to specify the leading part of the source strings: s1 = "aaaa bbb (xyz / cc.dd ee) : = 3.456e2"; s2 = "pqr : = 345.6"; s3 = "stu / (v w x) : = 345"; Last /@ StringSplit[{s1, s2, s3}] (* {"3.456e2","345.6","345"} *)

POSTED BY: Hans Milton

Rohit Namjoshi

Posted 4 years ago

Hope it explains my problem little better Not really. `1.23e2` is not a valid format for a number in WL. `1.23^2` or `1.2310^2` are valid. The code I provided converts the invalid form to the valid one and the result is a number, not a string. If you want a string result then just split the string StringSplit[#, "aaaa bbb (xyz / cc.dd ee) : = "] & /* First /@ {s1, s2, s3} (* {"3.456e2", "345.6", "345"} *)

POSTED BY: Rohit Namjoshi

S G

Posted 4 years ago

POSTED BY: S G

Rohit Namjoshi

Posted 4 years ago

How about extract[s_] := s // StringSplit[#, "aaaa bbb (xyz / cc.dd ee) : = "] & // First // Read[StringToStream[#], Number] & s1 = "aaaa bbb (xyz / cc.dd ee) : = 3.456e2" s2 = "aaaa bbb (xyz / cc.dd ee) : = 345.6" s3 = "aaaa bbb (xyz / cc.dd ee) : = 345" extract /@ {s1, s2, s3} (* {345.6, 345.6, 345} *)

How about

extract[s_] := 
 s // StringSplit[#, "aaaa bbb (xyz / cc.dd ee) : = "] & // First // 
  Read[StringToStream[#], Number] &

s1 = "aaaa bbb (xyz / cc.dd ee) : = 3.456e2"
s2 = "aaaa bbb (xyz / cc.dd ee) : = 345.6"
s3 = "aaaa bbb (xyz / cc.dd ee) : = 345"

extract /@ {s1, s2, s3}
(* {345.6, 345.6, 345} *)

POSTED BY: Rohit Namjoshi

Updating Name

Posted 4 years ago

POSTED BY: Updating Name

Rohit Namjoshi

Posted 4 years ago

Well, now you have changed the requirements. It would have been better if your original question stated the requirements clearly and completely. In the `s4` example there is a newline `\n` character separating the two cases. Is that always true or can `s4` be like this? s4 = "pqr : = 3 aaaa bbb (xyz / cc.dd ee) : = 3456e2"; or s4 = "pqr : = 3aaaa bbb (xyz / cc.dd ee) : = 3456e2"; Is the number always preceded by `: =` or are there other possible character sequences? If there is always a newline and always preceded by `: =` then (s4 // StringSplit[#, " : = " \| "\n"] &)[[2 ;; ;; 2]] (* {"3", "3456e2"} ) That will extract the numbers as strings, you can convert to numeric by mapping Read[StringToStream[#], Number] & /@ {"3", "3456e2"} ( {3, 345600} ) s5 = "pqr : = 3 aaaa bbb (xyz / cc.dd ee) : = 3456e2 abc : = 345.6"; (s5 // StringSplit[#, " : = " \| "\n"] &)[[2 ;; ;; 2]] ( {"3", "3456e2", "345.6"} *)