1.概念：由一組連續字符形成的數據。
COBOL中不需要對字符串添加任何結束標志。
2、使用STRING語句合並字符串
STRING
FIRST-NAME DELIMITED BY SAPCE
' ' DELIMITED BY SIZE
LAST-NAME DELIMITED BY SPACE
INTO FULL-NAME.
其中：DELIMITED BY的SPACE選項用於截掉字符串前后的空格。
SIZE用於將合並的字符串全部內容合並
' ' DELIMITED BY SIZE：是在FULLname中添加一個空格
3、相應的UNSTRING語句拆分字符串
UNSTRING FULL-NAME
DELIMITED BY ' '
INTO FIRST-NAME
LAST-NAME.
DISPLAY 'FULL NAME:',FULL-NAME.
DISPLAY 'FIRST NAME:',FIRST-NAME.
DISPLAY 'LAST NAME:'LAST-NAME.
4.用INSPECT語句替換字符串
主要對字符串中的指定部分進行替換。
例：
DATA DIVISION.
WORKING-STORAGE SECTION
01 DATE1 PIC X(10).
01 YEAR PIC X(4).
01 MONTH PIC X(2).
01 DAY1 PIC X(2).
01 TEST-STRING PIC X(10).
01 SOURCE-STRING PIC X(10).
PROCEDURE DIVISION
MOVE '2008/01/15' TO DATE1.
UNSTRING DATE1
DELIMITED BY '/'
INTO YEAR
MONTH
DAY1.
DISPLAY 'DATE:',DATE1.
DISPLAY 'YEAR:',YEAR.
DISPLAY 'MONTH:',MONTH.
DISPLAY 'DAY:',DAY1.
MOVE 'ABCD0A0B8B' TO TEST-STRING.
DISPLAY 'BEFORE INSPECT:',TEST-STRING.
MOVE TEST-STRING TO SOURCE-STRING.
INSPECT SOURCE-STRING
REPLACING ALL 'A' BY 'B'.
INSPECT SOURCE-STRING
REPLACING ALL '0' BY '_'.
INSPECT SOURCE-STRING
REPLACING LEADING 'B' BY '*'.
INSPECT SOURCE-STRING
REPLACING FIRST '*' BY '$'.
DISPLAY 'AFTER INSPECT:'SOURCE-STRING.
STOP RUN.
對全體數據進行替換：INSPECT SOURCE-STRING REPLACING ALL 'A' BY 'B'.
對開始數據進行替換：INSPECT SOURCE-STRING REPLACING LEADING 'A' BY 'B'.
對首個字符進行替換：INSPECT SOURCE-STRING REPLACING FIRST 'A' BY 'B'.
5.字符串替換
以原字符串的字符為基礎進行格式轉換。
a、大小寫轉換
例： FUNCTION LOWER-CASE(TEST-STRING) TO NEW-STRING.
FUNCTION UPPER-CASE(TEST-STRING) TO NEW-STRING.
b、將字符串轉換為具體數值
COMPUTE NUM-O1 =
FUNCTION NUMVAL(NUM-STR-01).
DISPLAY 'CONVERT AFTRE:',NUM-O1.
6.子字符串
相當於原字符串的一個子集。
例：MOVE '2008/09/23' TO DATE.
MOVE DATE(1：4) TO YEAR.
MOVE DATE(6：2) TO MONTH.
MOVE DATE(9： ) TO DAY. //表示從第9位到字符結束
7.通過MAX和MIN得到最大和最小字符串
MOVE FUNCTION MAX(STR-1 STR-2 STR-3) TO MAX-STR.
MOVE FUNCTION MIN(STR-1 STR-2 STR-3) TO MIN-STR.
MOVE FUNCTION MAX(NUM-1 NUM-2 NUM-3) TO MAX-STR.
MOVE FUNCTION MIN(NUM-1 NUM-2 NUM-3) TO MIN-STR.
8.求取字符串的長度
使用FUNCTION LENGTH或者LENTH OF 得到字符串的長度。
例：
MOVE FUNCTION LOWER-CASE(TEST-STRING) TO NEW-STRING.
DISPLAY 'NEW-STRING:',NEW-STRING.