suggestion of regex pattern

Re-reading your question and taking a wild guess, perhaps you are looking
for parse() and eval() ...

xyz <- data.frame( a=c(1,2), b=c(3,4))
xyz

  a b
1 1 3
2 2 4

expp <- parse(text="xyz$a > 1 & xyz$b == 4")   # turn a string into an
expression
expp

expression(xyz$a > 1 & xyz$b == 4)

xyz[eval(expp), ]                              # evaluate an expression in
place
  a b
2 2 4

... but really, it's just a guess at what you might be trying to do.

B.




On Apr 18, 2015, at 1:30 PM, Boris Steipe <boris.steipe at utoronto.ca>
wrote:

Sorry - it's not entirely clear to me what you need to do.

See here for some hints on how to ask questions on this list. I'm sure

we'll be able to help quickly.

http://adv-r.had.co.nz/Reproducibility.html

http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example

(and don't post in HTML   :-)


B.

On Apr 18, 2015, at 11:10 AM, Fernando Gama <f.fabiogama88 at gmail.com>

wrote:

Hello Boris,

thanks for your response.

So, firstly considered that  i've been input a set of serches strings

(.txt format) and i'm using regex to transform in a suitable  format to my
script. This part is a final part of my code and i wish putting in input to
a subset.

(.txt formatted)

---- STRINGS (INPUT)

[1]  "municipio =='Limeira' "
[2]  "municipio =='Limeira' & mesincident =='marco' "
[3]  "?municipio =='Limeira' & mesincident =='marco' & trechoklmetros >

1.00 12.300"

...
..
..
..
[n] "......"

--------------

desired_fomart <- ?it will reveice all strings to filter in a dataset

by subset below:

a loop each line:

subset(dataset_read, desired_fomart[i])

My question: taking into consideration this cenario, in your oppinion

your reply is my suitable for my problem, whereas i will to map each value
in database?

Once again, thank so much! :)

2015-04-18 11:04 GMT-03:00 Boris Steipe <boris.steipe at utoronto.ca>:
This is not a regular expression but simply a conjunction (sequence of

'&') of logical expressions. Moreover it's not wrong. Consider:

xyz <- data.frame(municipio = c('Limeira'), mesincident = c('marco'),

trechoklmetros = c(3.00, -4.00, 30))

xyz

 municipio mesincident trechoklmetros
1   Limeira       marco              3
2   Limeira       marco             -4
3   Limeira       marco             30


xyz$municipio =='Limeira' & xyz$mesincident =='marco' &

xyz$trechoklmetros > 1.00

[1]  TRUE FALSE  TRUE

xyz$municipio =='Limeira' & xyz$mesincident =='marco' &

xyz$trechoklmetros > 1.00 & xyz$trechoklmetros <= 12.3

[1]  TRUE FALSE FALSE


If there's a problem it seems to be elsewhere.
Cheers,
Boris


On Apr 17, 2015, at 4:22 PM, Fernando Gama <f.fabiogama88 at gmail.com>

wrote:

Hello,

I have benn problems to construct the pattern for this:

municipio =='Limeira' & mesincident =='marco' & trechoklmetros > 1.00

12.300

I would like:

municipio =='Limeira' & mesincident =='marco' & trechoklmetros > 1.00
*& **trechoklmetros
<= *12.300
?
?Any suggestion??


--
Att,

Fernando Gama da Mata

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