Obtaining different object from same file
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Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 35/100
Research direction
Start by reproducing the two data.table::fread calls from the report with the same tab-delimited numeric table, then compare their results with base read.table(). No source file or test is named, so trace the fread entry point and numeric parsing path to determine why repeated reads differ. Done means the cause is documented and repeated numeric reads are made consistent, with a regression test for the reported case.
Written by the indexing model from the issue text.
Description
Hi,
probably a very simple issue to fix but I am strugling to solve:
I have a txt numeric table with column header.
identical(
data.table::fread(fileName,sep='\t',header = T,check.names = F,colClasses = 'numeric'),
data.table::fread(fileName,sep='\t',header = T,check.names = F,colClasses = 'numeric'))
return FALSE most of the time
while
identical(
data.table::fread(fileName,sep='\t',header = T,check.names = F,colClasses = 'character'),
data.table::fread(fileName,sep='\t',header = T,check.names = F,colClasses = 'character'))
return always TRUE
On the other hand base read.table() does not have this issue (but it's way slower).
I would prefere to avoid loading the table as character to coerce it to numeric later (because of speed, otherwise I would have used read.table).
Any suggestion on how to read the same file twice and obtain identical objects (and why this is happening)?
Thank you in advance for help,
Luigi
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