在條形圖中減少x軸刻度（標籤）的數量

Question

我正在使用格子包中的條形圖。我有10年的時間序列數據，我希望x軸以六個月的間隔顯示格式％b-％Y。這是平凡完成在xyplot（給定日期的DateVector向量）與語法如：然而

scales=list(x=list(format = "%b-%Y",tick.number = length(DateVector)/2)) 

條形圖忽略用於通過設計因素tick.number選項，所以x軸變得不可讀用於大量數據的標籤。我如何減少滴答和/或滴答標籤的數量？

下面是一個簡單的例子，再現了我的問題，有數據如下（將數據保存爲Testrr.csv運行，道歉，如果這是錯誤的格式，這是我第一次;）

library(lattice) 

inptTrans <- read.csv("Testrr.csv") 
inptTrans$NotherTime <- as.Date(as.character(inptTrans$TransDateS),"%m/%d/%Y") 
xyp2 <- barchart (NumE+NumF~ NotherTime, data=inptTrans, main = sprintf("Total") 
        ,type='r',xlab = '',ylab='',col=c('red','black') 
        ,horizontal=FALSE 
        ,scales=list(x=list(rot=45,cex=1.0 , 
           labels=format(inptTrans$NotherTime,"%b-%Y"),tick.number=2) 
        ) 
        ,key=list(text = list(c("Num F","Num E")) 
        ,rectangle=list(col=c('black','red')),columns = 2 
        ,corner = c(0.05,-0.11),lty = c(1),lwd=3) 
        ,stack=TRUE 
       ) 

png(sprintf('Testrr.png'),width = 900, height = 750) 
print(xyp2) 
dev.off() 

Testrr .csv：

TransDateS,NumTot,NumF,NumE 
01/15/2003,339486,18478,293879 
02/15/2003,343761,16430,295272 
03/15/2003,413700,17924,356004 
04/15/2003,432741,18260,377046 
05/15/2003,465439,18721,406632 
06/15/2003,490699,18276,424773 
07/15/2003,507818,18354,440237 
08/15/2003,506530,17391,437386 
09/15/2003,481039,17809,411568 
10/15/2003,483364,19507,412902 
11/15/2003,392189,16308,329675 
12/15/2003,444249,18342,367489 
01/15/2004,364662,20009,308456 
02/15/2004,389718,16894,329946 
03/15/2004,511386,20207,434052 
04/15/2004,525563,19867,452646 
05/15/2004,538570,17557,463289 
06/15/2004,620868,20386,535523 
07/15/2004,581368,20844,500511 
08/15/2004,580773,19687,495930 
09/15/2004,523992,21322,442304 
10/15/2004,507288,18907,427265 
11/15/2004,489571,19135,409818 
12/15/2004,510904,21213,419328 
01/15/2005,419417,21930,351257 
02/15/2005,446402,19600,374778 
03/15/2005,581109,22655,486727 
04/15/2005,574275,21263,487661 
05/15/2005,617399,21033,524466 
06/15/2005,688876,26999,584782 
07/15/2005,610606,20712,516127 
08/15/2005,670746,23171,562919 
09/15/2005,601594,23769,499257 
10/15/2005,537107,21057,446620 
11/15/2005,517340,22378,421351 
12/15/2005,507610,22002,403392 
01/15/2006,409802,25032,334607 
02/15/2006,429196,23383,350498 
03/15/2006,567056,27528,461193 
04/15/2006,502403,24994,415797 
05/15/2006,578793,27765,480468 
06/15/2006,603134,31641,501012 
07/15/2006,507408,25796,423143 
08/15/2006,557500,31435,460225 
09/15/2006,475884,30448,386443 
10/15/2006,469092,31648,385751 
11/15/2006,432720,36363,349832 
12/15/2006,422369,30619,335706 
01/15/2007,365297,38993,302488 
02/15/2007,372276,34855,308599 
03/15/2007,455525,39038,377113 
04/15/2007,431043,36892,363764 
05/15/2007,473539,42371,401959 
06/15/2007,483341,44540,408415 
07/15/2007,441046,43735,373058 
08/15/2007,446111,48509,375242 
09/15/2007,341554,45252,283456 
10/15/2007,365869,55746,304820 
11/15/2007,333946,57399,274292 
12/15/2007,309551,51137,252391 
01/15/2008,270806,70554,229161 
02/15/2008,289606,66395,245970 
03/15/2008,328369,65904,279960 
04/15/2008,353531,78510,308293 
05/15/2008,375080,81284,328119 
06/15/2008,390034,80175,342170 
07/15/2008,378648,85689,334255 
08/15/2008,363756,83357,321556 
09/15/2008,350942,79301,309385 
10/15/2008,330164,75568,293867 
11/15/2008,252408,67388,222510 
12/15/2008,296037,65057,261619 
01/15/2009,222048,69380,201462 
02/15/2009,247591,77532,224236 
03/15/2009,305516,57897,277544 
04/15/2009,322308,65778,295160 
05/15/2009,335134,78854,305599 
06/15/2009,386702,93204,353285 
07/15/2009,391393,91153,358731 
08/15/2009,361150,77043,329656 
09/15/2009,360568,79893,327923 
10/15/2009,374886,90766,339969 
11/15/2009,342502,77895,305321 
12/15/2009,330770,81255,300899 
01/15/2010,238132,94309,220064 
02/15/2010,261558,81167,241123 
03/15/2010,363432,103052,335172 
04/15/2010,385535,100984,355852 
05/15/2010,381303,95408,350883 
06/15/2010,416893,94812,376190 
07/15/2010,297810,94574,278054 
08/15/2010,313494,98536,291501 
09/15/2010,301782,110154,280312 
10/15/2010,279117,80204,260114 
11/15/2010,270178,67700,250713 
12/15/2010,301323,67770,279877 
01/15/2011,232283,78998,219762 
02/15/2011,236917,64257,223213 
03/15/2011,312669,80275,295648 
04/15/2011,317720,77881,301463 
05/15/2011,332220,76017,315955 
06/15/2011,364962,79413,347253 
07/15/2011,320199,67812,305785 
08/15/2011,352555,74725,337283 
09/15/2011,316858,82664,303357 
10/15/2011,293425,69684,281407 
11/15/2011,279320,73735,267671 
12/15/2011,295369,70498,282722 
01/15/2012,238417,73051,229405 
02/15/2012,267105,65015,256719 
03/15/2012,328104,63709,315019 
04/15/2012,330508,58175,318258 
05/15/2012,369418,65886,356174 
06/15/2012,361304,59515,348708 
07/15/2012,305613,49700,295448 
08/15/2012,227541,35801,219883 

Answer 1

參數tick.number實際上只是一個關於放置刻度線的建議。在這種情況下，使用at參數可能會產生更一致的結果。

如果你想繪製每六個標籤，首先創建一個矢量索引序列：

okLabs <- seq(1, nrow(inptTrans), by = 6) 
okLabs 
[1] 1 7 13 19 25 31 37 43 49 55 61 67 73 79 85 91 97 103 109 115 

那麼你可以傳遞okLabs到at參數，並使用它來子集的labels（這裏的scales列表被分配到一個對象，可以傳遞給scales參數）：

scalesList <- list(x = list(rot = 45, cex = 1.0, 
    labels = format(inptTrans$NotherTime, "%b-%Y")[okLabs], at = okLabs)) 

barchart (NumE+NumF~ NotherTime, data=inptTrans, main = sprintf("Total") 
       ,type='r',xlab = '',ylab='',col=c('red','black') 
       ,horizontal=FALSE 
       ,scales= scalesList 
       ,key=list(text = list(c("Num F","Num E")) 
       ,rectangle=list(col=c('black','red')),columns = 2 
       ,corner = c(0.05,-0.11),lty = c(1),lwd=3) 
       ,stack=TRUE 
      ) 

請注意，當您嘗試繪製的數據中缺少（NA）值時，此代碼將無法正常工作。爲此，您可以嘗試省略丟失數據的行並從該子集創建新的data.frame。