parsing flowFrame@description in flowCore
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Entering edit mode
Robert Baer ▴ 70
@robert-baer-4660
Last seen 22 months ago
United States

# flowCore’ version 1.38.1

Steps to reproduce:

1. Read an .fcs file created with a BioRad S3 cell sorter using f <- read.FCS(.)

# Names of  in flowFrame

names(f@description)
  [1] "FCSversion"        "$BEGINANALYSIS"    "$ENDANALYSIS"     
  [4] "$BEGINDATA"        "$ENDDATA"          "$BEGINSTEXT"      
  [7] "$ENDSTEXT"         "$NEXTDATA"         "$DATATYPE"        
 [10] "$MODE"             "$PAR"              "$BYTEORD"         
 [13] "$TOT"              "$SYS"              "$CYT"             
 [16] "$CYTSN"            "$INST"             "$P1N"             
 [19] "$P1S"              "$P1B"              "$P1R"             
 [22] "$P1E"              "$P1G"              "$P1CALIBATION"    
 [25] "$P2N"              "$P2S"              "$P2B"             
 [28] "$P2R"              "$P2E"              "$P2G"             
 [31] "$P2CALIBATION"     "$P3N"              "$P3S"             

...         
[145] "$P21G"             "$ETIM"             "$BTIM"            
[148] "$DATE"             "$SPILLOVER"        "FILENAME"         
[151] "transformation"    "flowCore_$P1Rmax"  "flowCore_$P1Rmin" 
[154] "flowCore_$P2Rmax"  "flowCore_$P2Rmin"  "flowCore_$P3Rmax" 
[157] "flowCore_$P3Rmin"  "flowCore_$P4Rmax"  "flowCore_$P4Rmin" 
[160] "flowCore_$P5Rmax"  "flowCore_$P5Rmin"  "flowCore_$P6Rmax" 
[163] "flowCore_$P6Rmin"  "flowCore_$P7Rmax"  "flowCore_$P7Rmin" 
[166] "flowCore_$P8Rmax"  "flowCore_$P8Rmin"  "flowCore_$P9Rmax" 
[169] "flowCore_$P9Rmin"  "flowCore_$P10Rmax" "flowCore_$P10Rmin"
[172] "flowCore_$P11Rmax" "flowCore_$P11Rmin" "flowCore_$P12Rmax"
[175] "flowCore_$P12Rmin" "flowCore_$P13Rmax" "flowCore_$P13Rmin"
[178] "flowCore_$P14Rmax" "flowCore_$P14Rmin" "flowCore_$P15Rmax"
[181] "flowCore_$P15Rmin" "flowCore_$P16Rmax" "flowCore_$P16Rmin"
[184] "flowCore_$P17Rmax" "flowCore_$P17Rmin" "flowCore_$P18Rmax"
[187] "flowCore_$P18Rmin" "flowCore_$P19Rmax" "flowCore_$P19Rmin"
[190] "flowCore_$P20Rmax" "flowCore_$P20Rmin" "flowCore_$P21Rmax"
[193] "flowCore_$P21Rmin" "GUID" 

# Now try to access this data and note a strange parsing problem

# i.e., some fields seem to have extra $ character and require backwards apostrophe " ` "

# It seems this is not intended, but I don't know if this is a "file reading" or "file writing" problem"

# It certainly is in net a "file parsing" problem

# Example

> f@description$DATE
NULL

# But with extra $ and back single quote

> f@description$`$DATE`
[1] "17-May-2016"

# on the other hand some things work as expected

> f@description$GUID
[1] "2016-05-17 b16.fcs"

> f@description$FILENAME
[1] "./fullFCS/2016-05-17 b16.fcs"

#  Another broken one:

> f@description$SPILLOVER
NULL

#  The oddball fix
> f@description$`$SPILLOVER`
     FL1-AREA FL2-AREA FL3-AREA FL4-AREA
[1,]        1        0        0        0
[2,]        0        1        0        0
[3,]        0        0        1        0
[4,]        0        0        0        1

 

Question:  Is this a flowCore parsing problem or an S3 Cell Sorter writing problem?   And obviously, is there a way to improve this parsing behavior?

Thanks,

Rob Baer

Professor of Physiology

AT Still University of Health Sciences

 

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

flowCore’ version 1.38.1  running on Windows 10 in US locale

It could be important that I'm running inside RStudio 0.99.893

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

> sessionInfo()
R version 3.3.0 (2016-05-03)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)

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

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

other attached packages:
[1] flowViz_1.36.2  lattice_0.20-33 flowCore_1.38.1 sfsmisc_1.1-0  

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.5         matrixStats_0.50.2  mvtnorm_1.0-5      
 [4] corpcor_1.6.8       rrcov_1.3-11        MASS_7.3-45        
 [7] grid_3.3.0          stats4_3.3.0        pcaPP_1.9-60       
[10] KernSmooth_2.23-15  graph_1.50.0        hexbin_1.27.1      
[13] latticeExtra_0.6-28 robustbase_0.92-5   RColorBrewer_1.1-2 
[16] tools_3.3.0         Biobase_2.32.0      DEoptimR_1.0-4     
[19] parallel_3.3.0      BiocGenerics_0.18.0 cluster_2.0.4      
[22] IDPmisc_1.1.17     

 

FCS file flowcore @description • 1.1k views
ADD COMMENT
3
Entering edit mode
Jiang, Mike ★ 1.3k
@jiang-mike-4886
Last seen 2.6 years ago
(Private Address)

It is part of the FCS Standard.

>The '$' character flags this keyword as a standard FCS keyword.

So flowCore simply reads the keyword as it is in the original FCS TEXT segment. 

To avoid back ticks,  you can use "[[" instead "$"  to index the element of the list.

Also accessing the slot of S4 object directly through `@` operator makes your code less robust, try to use the public API when it is available.

In this case, 'keyword' method should be used.

 

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