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Hello, I would like to know how to calculate the price variation from one period to another. Example:
Year | Price
2007 | 25
2008 | 30
2009 | 7
2010 | 15
... |...|...
The new column would be:
Year | Price | Change
2007 | 25 | 25-0 = 25
2008 | 30 | 30-25 = 5
2009 | 7 | 7-30 = -23
2010 | 15 | 15-7 = 8
... |... |...|...
I have no idea how to do that. Thanks in advance !
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You can use the function diff():
#dados
df <- data.frame(Ano = c(2007,2008,2009,2010), Preço = c(25,30,7,15))
diff(df$Preço)
# [1] 5 -23 8
The function diff() ignores the first element. To get the result of your example, we can use the function append() to add the first element:
df$Variação <- append(df$Preço[1], diff(df$Preço))
df
# Ano Preço Variação
# 1 2007 25 25
# 2 2008 30 5
# 3 2009 7 -23
# 4 2010 15 8
Browser other questions tagged r calculus helper diff rowsorter
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Thanks for the answer ! But I forgot to put a part of the problem. Company | Year | Price | Variation 1 |2007 | 25 | 25-0 = 25 1 | 2008 | 30 | 30-25 = 5 1 |2009 | 7 | 7-30 = -23 1 |2010 | 15 | 15-7 = 8 2 |2007 | 20 | 20-0 = 20 2 | 2008 | 27 | 27-20 = 7 2 |2009 | 7 | 7-27 = -20 2 |2010 | 20 | 20-7 = 13 ... |... |...|... There are several companies. This command would solve as well ??
– RxT