SAS函數的介紹 INDEX functions

[INDEX]:找出字串中，某一個字或字串首次出現的位子

Function: INDEX(var,"value")

我們可以藉由他找出字串中是否有我們感興趣的字或是字串。

舉例來說：

found_A_first = index(X, "A") *found_A_first會回應變相X首次出現的位子;

當我們想要找字串中是否有我們感興趣的字或是字串時，

也可以利用index，

舉例來說：

if index(X, "A") > 0 then found_A = 1; else  found_A = 0;

*若A有出現在X中，那index(X,"A")的回應值會大於0，因此語法可以這樣下;

若需要找出有A or B字元或是A&B字元可以利用

if found_A+found_B>= 1  then found_A_or_B = 1; else  found_A_or_B = 0;

if found_A+found_B=2  then found_A_and_B = 1; else  found_A_and_B = 0;

data a;

input X $ ;

cards;

AB

ABC

BCD

BCDE

CD

;

run;

data b;

set a;

found_A_first = index(X, "A");

found_B_first = index(X, "B");

found_AB_first = index(X, "AB");

found_BC_first = index(X, "BC");

if index(X, "A") > 0 then found_A = 1; else  found_A = 0;

if index(X, "B") > 0 then found_B = 1; else  found_B = 0;

if index(X, "AB") > 0 then found_AB = 1; else  found_AB = 0;

if found_A+found_B>= 1  then found_A_or_B = 1; else  found_A_or_B = 0;

if found_A+found_B=2  then found_A_and_B = 1; else  found_A_and_B = 0;

run;

proc print data = b;

run;