title: can't seem to save chart_Series() as pdf inside a for loop
body: <p>I can't seem to save chart_Series as pdf using the pdf() and dev.off() inside a for-loop. However, outside the for-loop if I run the code inside the hash box one at a time with incremental value of "i",I am able to produce the graphs. What am I doing wrong?</p>
  
  <pre><code>rm(list = ls(all = TRUE))
  setwd("~/Documents/R")
  library(tseries)
  library(PerformanceAnalytics)
  library(quantmod)
  library(xts)
  library(TTR)
  library(Hmisc)
  library(Quandl)
  
  Quandl.api_key("yourKeyHere")
  
  startDate = "2012-01-01"
  
  symbols = c(
    "ACAD",
    "ACM" ,
    "AL",
    "ALB",
    "AMD",
    "AMKR",
    "AVP",
    "BC",
    "BID",
    "BKD",
    "BWA" ,
    "BYD" ,
    "CAA" ,
    "CAR" ,
    "CAVM",
    "CBL" ,
    "CF"  ,
    "CHK" ,
    "CIEN"
  )
  
  EOD &lt;- function(symbols, startDate){
    for (i in 1:length(symbols)){
      stk &lt;-Quandl(paste("EOD/",symbols[i],sep=""), start_date =   startDate, type='xts')[,c(8,9,10,11,12)]
      sp &lt;-data.frame(Date=index(stk), round(coredata(stk), digits=3))
      colnames(sp) &lt;- c("Date","Open", "High", "Low", "Close", "Volume")
      setwd("~/Documents/R/STK/csv/eq")
      write.csv(sp, paste(paste0(symbols[i]),".csv", sep=""), row.names=FALSE)
    }
  }
  
  EOD(symbols, startDate)
  
  for (i in 1:length(symbols)){
    setwd("~/Documents/R/STK/csv/eq")
    stk1 &lt;-getSymbols.csv(symbols[i], src="csv", from = startDate,    col.names=c("Open","High","Low","Close","Volume"), auto.assign =FALSE)
    colnames(stk1) &lt;- c("Open", "High", "Low", "Close", "Volume")
  
    ##########################################################
    setwd("~/Documents/R/STK/zs")
    name &lt;- paste0(symbols[i])
    pdfname &lt;- paste(name, ".pdf", sep="")
    pdf(file=pdfname)
    chart_Series(stk1 , subset = "2016-01-01::", name = paste0(symbols[i]))
    dev.off()
    ##########################################################
  }
  
  ######################################################
  R version 3.3.2 (2016-10-31)
  Platform: x86_64-apple-darwin13.4.0 (64-bit)
  Running under: macOS Sierra 10.12.5
  
  locale:
  [1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
   [1] KFAS_1.2.8                    Quandl_2.9.0                      reshape2_1.4.2                Hmisc_4.0-3                  
   [5] ggplot2_2.2.1                 Formula_1.2-1                 survival_2.41-3               quantstrat_0.9.1739          
   [9] foreach_1.4.3                 blotter_0.9.1741              FinancialInstrument_1.2.0     quantmod_0.4-10              
   [13] TTR_0.23-1                    PerformanceAnalytics_1.4.3541 xts_0.9-7                     zoo_1.8-0                    
   [17] tseries_0.10-41               timeSeries_3022.101.2         timeDate_3012.100             lattice_0.20-35              
  </code></pre>
  
  <p>loaded via a namespace (and not attached):
       [1] splines_3.3.2       colorspace_1.3-2    htmltools_0.3.6     mgcv_1.8-17         base64enc_0.1-3     rlang_0.1.1         foreign_0.8-69<br>
       [8] RColorBrewer_1.1-2  plyr_1.8.4          stringr_1.2.0       munsell_0.4.3       gtable_0.2.0        htmlwidgets_0.8     codetools_0.2-15<br>
      [15] labeling_0.3        latticeExtra_0.6-28 knitr_1.16          curl_2.6            htmlTable_1.9       Rcpp_0.12.11        acepack_1.4.1<br>
      [22] scales_0.4.1        backports_1.1.0     checkmate_1.8.2     jsonlite_1.5        gridExtra_2.2.1     digest_0.6.12       stringi_1.1.5<br>
      [29] grid_3.3.2          quadprog_1.5-5      tools_3.3.2         magrittr_1.5        lazyeval_0.2.0      tibble_1.3.3        cluster_2.0.6<br>
      [36] Matrix_1.2-10       data.table_1.10.4   httr_1.2.1          iterators_1.0.8     R6_2.2.2            rpart_4.1-11        nnet_7.3-12<br>
      [43] nlme_3.1-131       </p>