R_and_bigint.R

# hit a snag time when working with session ids (represented as bigint in a database)

df <- read.csv("myData.csv", header=TRUE) # sid is the column 

"
> tail(df, n=1)$sid
[1] 2e+18
"

# WTF moment
"
> 2000000002775713071 == 2000000002775713073
[1] TRUE
"

# Treat as character class
df <- read.csv("myData.csv", header=TRUE, colClasses=c("sid"="character"))

"
> tail(df, n=1)$sid
[1] 2000000002775713071
"

# If we really needed to keep work with it as an integer (not in this case but...)

library(gmp)
mySid = as.bigq(tail(df, n=1)$sid, 19)
"
> mySid = as.bigq(tail(df, n=1)$sid, 19)
> mySid
Big Rational ('bigq') :
[1] 2000000002798018836/19
"