R help - May 2014 - Confusing behavior when using gsub to insert unicode character (minimal working example provided)

Can anyone help me understand the following behavior?

I want to replace the letter 'X' in
​the string ​
'text X' with '≥' (\u226
​5
).  The output from gsub is not what I expect.  It gives: "text ≥".

Now, suppose I want to replace the character '≤' in
​ the string​
'text ≤' with '≥'.  Then, gsub gives the expected, desired
output.

​What am I missing?

Thanks for any insight.
-tgs

Minimal Working Example:

string1 <- "text X"; string1
new_string1 <- gsub("X","\u2265",string1); new_string1

string2 <- "text \u2264"; string2
new_string2 <- gsub("\u2264","\u2265",string2);
new_string2

charToRaw(new_string1)
charToRaw(new_string2)

sessionInfo()

## OUTPUT
> string1 <- "text X"; string1
[1] "text X"
> new_string1 <- gsub("X","\u2265",string1);
new_string1
[1] "text ≥"
> string2 <- "text \u2264"; string2
[1] "text ≤"
> new_string2 <- gsub("\u2264","\u2265",string2);
new_string2
[1] "text ≥"
> charToRaw(new_string1)
[1] 74 65 78 74 20 e2 89 a5
> charToRaw(new_string2)
[1] 74 65 78 74 20 e2 89 a5
> sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United
States.1252    LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                           LC_TIME=English_United
States.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] tools_3.0.2

	[[alternative HTML version deleted]]

On May 28, 2014, at 7:25 PM, Thomas Stewart wrote:
> Can anyone help me understand the following behavior?
> 
> I want to replace the letter 'X' in
> ?the string ?
> 'text X' with '?' (\u226
> ?5
> ).  The output from gsub is not what I expect.  It gives: "text
???".
> 
> Now, suppose I want to replace the character '?' in
> ? the string?
> 'text ?' with '?'.  Then, gsub gives the expected, desired
output.
> 
> ?What am I missing?
> 
> Thanks for any insight.
> -tgs
> 
> Minimal Working Example:
> 
> string1 <- "text X"; string1
> new_string1 <- gsub("X","\u2265",string1);
new_string1
Try this instead:
> new_string1 <- gsub("X","\\\u2265",string1);
new_string1
[1] "text ?"

Each "\" needs to be escaped, both the "\" in \u2265 as well
as the "\" that escapes it.
> nchar("\\")
[1] 1
> nchar("\\\u2265")
[1] 2

You would be well-served by spending effort at reading:

?Quotes

-- 
David.
> 
> string2 <- "text \u2264"; string2
> new_string2 <- gsub("\u2264","\u2265",string2);
new_string2
> 
> charToRaw(new_string1)
> charToRaw(new_string2)
> 
> sessionInfo()
> 
> ## OUTPUT
> 
>> string1 <- "text X"; string1
> [1] "text X"
> 
>> new_string1 <- gsub("X","\u2265",string1);
new_string1
> [1] "text ???"
> 
>> string2 <- "text \u2264"; string2
> [1] "text ?"
> 
>> new_string2 <- gsub("\u2264","\u2265",string2);
new_string2
> [1] "text ?"
> 
>> charToRaw(new_string1)
> [1] 74 65 78 74 20 e2 89 a5
> charToRaw("\\\u2265")
[1] 5c e2 89 a5


> 
>> charToRaw(new_string2)
> [1] 74 65 78 74 20 e2 89 a5
> 
>> sessionInfo()
> R version 3.0.2 (2013-09-25)
> Platform: x86_64-w64-mingw32/x64 (64-bit)
> 
It was a good idea to post sessionInfo(), but it would have been even better to
have posted in plain text.

> 	[[alternative HTML version deleted]]
> 
-- 

David Winsemius
Alameda, CA, USA