非连续高度变量的变换

Question

我无法有效地转换样本中编码错误的高度变量。

变量编码如下：

如您所见，变量同时编码为英尺和英寸，其中 601 等于 6 英尺 1 英寸，511 等于 5 英尺 11 英寸等。

我的目标是将这些数字转换成英寸：

replace Height = 48 if Height == 400 
replace Height = 49 if Height == 401
replace Height = 50 if Height == 402
replace Height = 51 if Height == 403
.
.
.
replace Height = 83 if Height == 611

如何使用循环高效地编写代码？

Answer 1

下面的代码假定 Height 的每个观察值恰好包含三个数字：

tostring Height, generate(Height_string)
    /* Generate a new variable which is a string-version of Height
       (so that we can get the individual digits) */

generate feet = substr(Height_string, 1, 1)
    /* From the first character in the string, select one character */

generate inch = substr(Height_string, 2, 2)
    /* From the second character in the string, select two characters.
       An equivalent alternative would have been
       generate inch = substr(Height_string, -2, 2)
       which from the second to last character selects two characters */

destring feet inch, replace
    /* Convert these two new variables to numeric */

generate tot_inch = feet * 12 + inch
    /* Generate a new variable which measure only in inches. */

Answer 2

这可以作为纯数字运算在一行中完成。转换为字符串并再次转换回来是完全没有必要的。不需要循环。

generate wanted = 12 * floor(height/100) + mod(height, 100)

非连续高度变量的变换

Transformation of Non-Continuous Height Variable

transformation

stata