Extract numbers from char type

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Yoseph
Yoseph am 18 Okt. 2022
Kommentiert: Star Strider am 19 Okt. 2022
how can I extract the numbers from a character array value of '4.64 km' and return them as 4.64?

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Star Strider
Star Strider am 18 Okt. 2022
Bearbeitet: Star Strider am 18 Okt. 2022
Probably the easiest way —
s = '4.64 km';
c = regexp(s, '\d*\.\d*|\d*', 'match')
c = 1×1 cell array
{'4.64'}
n = str2double(c)
n = 4.6400
EDIT — (18 Oct 2022 at 19:38)
In the event any of the numbers are negative —
s = '4.64 -42 2 -3.14 km';
c = regexp(s, '(\-\d*|\d*)\.\d*|(\-\d*|\d*)', 'match')
c = 1×4 cell array
{'4.64'} {'-42'} {'2'} {'-3.14'}
n = str2double(c)
n = 1×4
4.6400 -42.0000 2.0000 -3.1400
.
  4 Kommentare
Walter Roberson
Walter Roberson am 19 Okt. 2022
darn I forgot the case of no period
Star Strider
Star Strider am 19 Okt. 2022
I saw that and wondered, however I did not change my answer, and just learned from the important parts of your syntax.

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Weitere Antworten (2)

Les Beckham
Les Beckham am 18 Okt. 2022
Or, in one line of code:
s = '4.64 km';
num = sscanf(s, '%f') % num will be a double
num = 4.6400
  1 Kommentar
Walter Roberson
Walter Roberson am 18 Okt. 2022
Yes this works well when the number is at the beginning. You can also put literal text into the format if you expect an exact match.
The suggestions to use regexp to extract the text of the number work well when you need flexibility.
In cases where you have tables of text see textscan() which can be used on a character vector that has embedded newlines.

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David Hill
David Hill am 18 Okt. 2022
a='4.65 km';
r=regexp(a,'\d*[.]*\d*','match');
str2num(r{1})
ans = 4.6500

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