根據標準獲取行數 - 特定年份的日期字段，按文本字段分組

Question

我有一份每日發佈的Excel報告，需要我總結並提供趨勢分析。此報告具有創建日期，工作項類型的工作項目清單。我如何計算2011年，2012年創建的工作項目？另外，如何通過工作項類型獲得計數？到目前爲止，我已經能夠加載Excel數據，並通過執行以下獲得的行數 -

library(gdata) 
wi20121812 = read.xls("WorkItemReport20121812.xls") 
nrow(wi20121812) 

樣本數據

> dput(head(workItemReport2)) 
structure(list(DocType = structure(c(6L, 7L, 6L, 6L, 8L, 6L), .Label = c("TYPE10WI", 
"TYPE11WI", "TYPE12WI", "TYPE13WI", "TYPE14WI", "TYPE1WI", "TYPE2WI", 
"TYPE3WI", "TYPE4WI", "TYPE5WI", "TYPE6WI", "TYPE7WI", "TYPE8WI", 
"TYPE9WI"), class = "factor"), CreatedDate = structure(c(7L, 
22L, 146L, 181L, 153L, 191L), .Label = c("1/10/12 15:43 AM/PM ", 
"1/10/12 16:06 AM/PM ", "1/10/12 5:28 AM/PM ", "1/10/12 5:56 AM/PM ", 
"1/11/12 19:51 AM/PM ", "1/11/12 5:26 AM/PM ", "1/12/11 21:58 AM/PM ", 
"1/12/12 11:08 AM/PM ", "1/12/12 5:41 AM/PM ", "1/12/12 9:56 AM/PM ", 
"1/13/12 14:01 AM/PM ", "1/13/12 15:08 AM/PM ", "1/13/12 15:11 AM/PM ", 
"1/13/12 8:51 AM/PM ", "1/16/12 10:27 AM/PM ", "1/16/12 10:28 AM/PM ", 
"1/16/12 16:37 AM/PM ", "1/16/12 7:52 AM/PM ", "1/18/12 15:02 AM/PM ", 
"1/18/12 16:03 AM/PM ", "1/18/12 16:13 AM/PM ", "1/19/11 19:23 AM/PM ", 
"1/20/12 10:48 AM/PM ", "1/20/12 12:23 AM/PM ", "1/20/12 8:38 AM/PM ", 
"1/23/12 5:53 AM/PM ", "1/24/12 15:18 AM/PM ", "1/24/12 8:23 AM/PM ", 
"1/24/12 8:58 AM/PM ", "1/25/12 11:38 AM/PM ", "1/25/12 5:28 AM/PM ", 
"1/26/12 13:48 AM/PM ", "1/26/12 15:53 AM/PM ", "1/26/12 15:58 AM/PM ", 
"1/26/12 16:13 AM/PM ", "1/26/12 16:18 AM/PM ", "1/26/12 7:33 AM/PM ", 
"1/27/12 7:48 AM/PM ", "1/3/12 17:48 AM/PM ", "1/3/12 18:33 AM/PM ", 
"1/3/12 9:07 AM/PM ", "1/30/12 11:22 AM/PM ", "1/30/12 22:52 AM/PM ", 
"1/30/12 23:10 AM/PM ", "1/31/12 19:54 AM/PM ", "1/31/12 20:39 AM/PM ", 
"1/31/12 5:42 AM/PM ", "1/31/12 9:42 AM/PM ", "1/4/12 14:02 AM/PM ", 
"1/4/12 9:52 AM/PM ", "1/5/12 13:42 AM/PM ", "1/5/12 17:42 AM/PM ", 
.... 
.... 
"9/6/12 9:02 AM/PM ", "9/7/12 11:48 AM/PM ", "9/7/12 12:58 AM/PM ", 
"9/7/12 13:52 AM/PM ", "9/7/12 15:07 AM/PM ", "9/7/12 15:12 AM/PM ", 
"9/7/12 15:22 AM/PM ", "9/7/12 15:47 AM/PM ", "9/7/12 15:52 AM/PM ", 
"9/7/12 8:42 AM/PM ", "9/7/12 9:32 AM/PM ", "9/8/11 23:43 AM/PM " 
), class = "factor")), .Names = c("DocType", "CreatedDate"), row.names = c(NA, 
6L), class = "data.frame") 
> 

Answer 1

您的問題的一部分仍未解答，「如何獲得工作項目類型」非常簡單。

res <- table(wi20121812[, "WorkItemType"]) 

這會給你一個簡單的表格，告訴你每個WorkItemType發生的頻率。如果你需要把它的比例，而不是結果絕對計數，運行prop.table（）：

prop.table(res) 

或者做兩者兼而有之：

res <- prop.table(table(wi20121812[, "WorkItemType"])) 

Answer 2

你可以使用ddply從plyr包：

res = ddply(df, "year", summarise, amount = length(year)) 

或使用count形成相同的包裝（這更容易）：

res = count(df, "year") 

其中df是data.frame包含您的數據，而year是包含分類變量的列名稱，該分類變量詳細說明在哪一年創建該行。