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Workshop 2.4: Data manipulation
Murray Logan
April 9, 2016
Table of contents
1 Data manipulation 1 2 Sorting data 2 3 Manipulating factors 7 4 Filtering 10 5 Reshaping data 15 6 Merging data 19 7 VLOOKUP 24 8 Aggregating data (pivot tables) 26 9 Transformations 36
- 1. Data manipulation
1.1. Important data manipulation libraries
Task Function Package Sorting
- rder()
base arrange() plyr Re-ordering factor levels factor(,levels=) base reorder(,new.order=) gdata Re-labelling factor(,lab=) base recode() car revalue(,replace=) plyr Re-naming columns colnames() base rename(,replace=) dplyr Filtering/Subsetting indexing base subset(,subset=,select=) base select(,...) dplyr Reshaping data melt(), cast() reshape2
1.2. Important data manipulation libraries
Task Function Package Merging/joining merge() base join() plyr Aggregating tapply() base