最新精选stata入门7流程语句.doc

7 流程语句 7.1循环语句:while 任务7.1：用循环语句编写程序，依次列出1，2，3，4，5 程序示例： *============================begin================================= capture drop count5 program count5 local i=1 //先将宏名为i的宏值设为1 while `i’=5 { //判断如果宏值`i’不大于5，就执行{}中的命令，否则跳开 display `i’ //要干的活是显示宏值`i’ local i=`i’+1 //重新设定宏名为i的宏值，令其等于`i’+1 } end *============================end================================== count5 1 2 3 4 5 看看这些结果，`i’最初设为1，因为1小于5，因此显示1；显示完毕紧随其后的命令，将i重新设定（即加上1），重新设定后`i’现在等于2，由于2仍然小于5，于是显示2，并再次重新设定i,…,直到`i’与6等价，不再小于等于5，跳出循环{}，执行end. 补充知识：数列的表示方法 2 just one number 1 2 3 three numbers 3 2 1 three numbers in reversed order .5 1 1.5 three different numbers 1 3 -2.17 5.12 four numbers in jumbled order 1/3 three numbers: 1, 2, 3 3/1 the same three numbers in reverse order 5/8 four numbers: 5, 6, 7, 8 -8/-5 four numbers: -8, -7, -6, -5 -5/-8 four numbers: -5, -6, -7, -8 -1/2 four numbers: -1, 0, 1, 2 1 2 to 4 four numbers: 1, 2, 3, 4 4 3 to 1 four numbers: 4, 3, 2, 1 10 15 to 30 five numbers: 10, 15, 20, 25, 30 1 2:4 same as 1 2 to 4 4 3:1 same as 4 3 to 1 10 15:30 same as 10 15 to 30 1(1)3 three numbers: 1, 2, 3 1(2)9 five numbers: 1, 3, 5, 7, 9 1(2)10 the same five numbers: 1, 3, 5, 7, 9 9(-2)1 five numbers: 9, 7, 5, 3, and 1 -1(.5)2.5 the numbers: -1, -.5, 0, .5, 1, 1.5, 2, 2.5 1[1]3 same as 1(1)3 1[2]9 same as 1(2)9 1[2]10 same as 1(2)10 9[-2]1 same as 9(-2)1 -1[.5]2.5 same as -1(.5)2.5 1 2 3/5 8(2)12 eight numbers: 1, 2, 3, 4, 5, 8, 10, 12 1,2,3/5,8(2)12 the same eight numbers 1 2 3/5 8 10 to 12 the same eight numbers 1,2,3/5,8,10 to 12 the same eight numbers 1 2 3/5 8 10:12 the same eight numbers 7.3循环语句:forvalues 程序示例： *============================begin================================= forvalues i=1/5 { display `i’ //和上一个命令完全等价，只是写法更简洁 } *============================end================================== 程序示例3： *============================begin================================= forvalues i=4 (-0.2) 0{ //起始值可大于终值，但步长应为负，步长可为小