g j=int((_n-1)/9)+1
bys j: g i=_n
reshape wide x,i(i) j(j)

*或者
g i=mod(_n-1,9)+1
g j=int((_n-1)/9)+1
reshape wide x,i(i) j(j)

非常感谢版主，实现的很完美

版主，我想请教您xtunitroot命令的一个例子
为何下面的两种实现结果不一致？
Method 1：

webuse pennxrate
xtunitroot llc lnrxrate if year>=1975, lags(aic 10) kernel(bartlett nwest)

RE1：
Levin-Lin-Chu unit-root test for lnrxrate
-----------------------------------------
Ho: Panels contain unit roots               Number of panels  =    151
Ha: Panels are stationary                   Number of periods =     29

AR parameter: Common                        Asymptotics: N/T -> 0
Panel means:  Included
Time trend:   Not included

ADF regressions: 10 lags
LR variance:     Bartlett kernel, 3.67 lags average
                 (chosen by Newey-West)
------------------------------------------------------------------------------
                    Statistic      p-value
------------------------------------------------------------------------------
Unadjusted t       -21.0454
Adjusted t*         10.4283        1.0000
------------------------------------------------------------------------------



Method 2：
webuse pennxrate
keep if year>=1975
xtunitroot llc lnrxrate , lags(10) kernel(bartlett nwest)

Levin-Lin-Chu unit-root test for lnrxrate
-----------------------------------------
Ho: Panels contain unit roots               Number of panels  =    151
Ha: Panels are stationary                   Number of periods =     29

AR parameter: Common                        Asymptotics: N/T -> 0
Panel means:  Included
Time trend:   Not included

ADF regressions: 10 lags
LR variance:     Bartlett kernel, 3.93 lags average
                 (chosen by Newey-West)
------------------------------------------------------------------------------
                    Statistic      p-value
------------------------------------------------------------------------------
Unadjusted t       -34.2127
Adjusted t*         -7.9811        0.0000
------------------------------------------------------------------------------

版主，还想请教您一下
如果第4列数据有一些缺省值，
应该如何变换为前3列数据？
谢谢