问题
Octave adds spaces with strcat
In Octave I run these commands:
strcat ("hel", " ", "lo")
I get this result:
ans = hello
Instead of what I expected:
ans = hel lo
strcat to me sounds like "concatenate strings". A space is a valid character, so adding a space should be OK. Matlab has the same behaviour, so it's probably intended.
I find it counter intuitive. Does this behavior makes sense?
回答1:
Hmm. It works how it is defined:
"strcat removes trailing white space in the arguments (except within cell arrays), while cstrcat leaves white space untouched. "
From http://www.gnu.org/software/octave/doc/interpreter/Concatenating-Strings.html
So the question could be: Should this behaviour be changed.
回答2:
strcat takes the input parameters and trims the trailing spaces, but not the leading spaces. if you pass a parameter as one or more spaces, they are collapsed to blank string.
That behavior is a manifestation of how "cellstr" works where spaces at the end are removed.
Work around 1
If you put the space up against the 'lo', it is a leading space and not removed.
strcat ("hel", " lo")
ans = hel lo
Work around 2
use cstrcat instead:
cstrcat("hel", " ", "lo")
ans = hel lo
Work around 3
Use printf, can be faster than strcat.
printf("%s%s%s\n", "hel", " ", "lo")
hel lo
来源：https://stackoverflow.com/questions/14025985/octave-strcat-ignores-added-spaces