示例df：
df <- data.frame(x = c(runif(10,0,2*pi),runif(10,0,360)), group = gl(n = 2, k = 10, labels =c("A","B")))
我想仅为群组x修改A（将其转换为度数）。使用base我就是这样做：
df <- within(df,x[group == "A"] <- x[group == "A"]*180/pi)
我想知道是否可以通过dplyr进行此操作。这是错的：
df <- df %>% filter(group == "A") %>% mutate(x = x*180/pi)
因为它只返回df的子集group == "A"。是否有一种（简单）方法可以做到这一点，或者这是base胜过dplyr以便于使用的情况？
答案 0 :(得分：3)
我们可以使用 protected void Button5_Click(object sender, EventArgs e)
{
dynamic rpt = new ReportDocument();
ApplyCRLogin(rpt);
DataSet dtu = new DataSet();
// Your Stored Procedure Here
// Bind dtu to the ObjReport
rpt .Database.Tables["Command"].SetDataSource(dtu.Tables[0]);
// Here Command is name which you can see inside Field Explorer in Crystal Report Design Mode
// Then Pass your SP parametrs
rpt.SetParameterValue("@dtFromDate", txtFromDate.Text);
rpt.SetParameterValue("@dtToDate", txtToDate.Text);
//After this Export your Crstal Report to PDF
ExportToPDF(rpt);
}
public void ApplyCRLogin(CrystalDecisions.CrystalReports.Engine.ReportDocument oRpt)
{
CrystalDecisions.CrystalReports.Engine.Database oCRDb = oRpt.Database;
CrystalDecisions.CrystalReports.Engine.Tables oCRTables = oCRDb.Tables;
CrystalDecisions.Shared.TableLogOnInfo oCRTableLogonInfo;
CrystalDecisions.Shared.ConnectionInfo oCRConnectionInfo = new CrystalDecisions.Shared.ConnectionInfo();
oCRConnectionInfo.DatabaseName = "DatabaseName";
oCRConnectionInfo.ServerName = "DBSRV_NAME";
oCRConnectionInfo.UserID = "UserID";
oCRConnectionInfo.Password = "Password";
foreach (CrystalDecisions.CrystalReports.Engine.Table oCRTable in oCRTables)
{
oCRTableLogonInfo = oCRTable.LogOnInfo;
oCRTableLogonInfo.ConnectionInfo = oCRConnectionInfo;
oCRTable.ApplyLogOnInfo(oCRTableLogonInfo);
}
}
来创建逻辑条件，并根据它进行算术运算或ifelse返回原始值。
else或者@AlexIoannides提到，可以使用df %>%
mutate(x = ifelse(group=="A", x*180/pi, x))
中的if_else，因此dplyr应该得到处理。
在type中，这可以通过就地分配来完成，并且应该更有效率。
data.table