[R] Some SQL Challenges

[Don MacQueen]

Don't understand what this has to do with SQL, or why you're asking 
for SQL solutions in an R mailing list, but here are some R 
suggestions.

(abbreviating "COLUMN" with "C")

At 11:40 AM -0700 8/3/09, JoK LoQ wrote:
>Hi,
>
>Im trying to complete a list of jobs using SQL Querries and some "if else"
>commands but im stucked in some steps. Could any of you give me some help?
>
>-in COLUMN1 change the format 20JAN2000:00:00:00 to 20JAN2000 and exclude
>every row that date is different from 20.

Assuming C1 contains character strings:
   C1 <- substring( C1, 1, 9)
   C1 <- C1[  substring(C1,1,2) == '20' ]


>-extract the first character in COLUMN2 and creat COLUMN3 with that value
>ex:
>COL2,COL3
>135,1
>461,4
>247,2

   C3 <- substring( C2, 1 ,1)
or
   C3 <- as.numeric( substring( C2, 1, 1) )


>-in every row in which COL3=5, value in COLUMN4=value in COLUMN5

C4[ C3==5] <- C5[ C3==5]


>-create COLUMN7 where if COLUMN6="north" then COLUMN7 value="N" else COLUMN7
>value="X"

C7 <- ifelse( C6 == "north" , "N", "X")


>
>Ill be grateful for any help, thnks
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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062