Delphi的字串類資料型態&函數

字串類的資料型態
Str1 : Char; // Holds a single character, small alphabet
Str2 : WideChar; // Holds a single character, International alphabet
Str3 : AnsiChar; // Holds a single character, small alphabet
Str4 : ShortString; // Holds a string of up to 255 Char’s
Str5 : String; // Holds strings of Char’s of any size desired
Str6 : AnsiString; // Holds strings of AnsiChar’s any size desired
Str7 : WideString; // Holds strings of WideChar’s of any size desired

ANSI標準字碼
Char Code Description
9 Tab
10 Line feed
13 Carriage return
‘ ‘ 32 Space
! 33 Exclamation mark
” 34 Quotation mark
# 35 Number sign
$ 36 Dollar sign
% 37 Percent sign
& 38 Ampersand
‘ 39 Apostrophe
( 40 Left parenthesis
) 41 Right parenthesis
* 42 Asterisk
+ 43 Plus sign
, 44 Comma
– 45 Hyphen-minus
. 46 Full stop
/ 47 Solidus
0 48 Digit zero
1 49 Digit one
2 50 Digit two
3 51 Digit three
4 52 Digit four
5 53 Digit five
6 54 Digit six
7 55 Digit seven
8 56 Digit eight
9 57 Digit nine
: 58 Colon
; 59 Semicolon
< 60 Less-than sign
= 61 Equals sign
> 62 Greater-than sign
? 63 Question mark
@ 64 Commercial at
A 65 Latin capital letter A
B 66 Latin capital letter B
C 67 Latin capital letter C
D 68 Latin capital letter D
E 69 Latin capital letter E
F 70 Latin capital letter F
G 71 Latin capital letter G
H 72 Latin capital letter H
I 73 Latin capital letter I
J 74 Latin capital letter J
K 75 Latin capital letter K
L 76 Latin capital letter L
M 77 Latin capital letter M
N 78 Latin capital letter N
O 79 Latin capital letter O
P 80 Latin capital letter P
Q 81 Latin capital letter Q
R 82 Latin capital letter R
S 83 Latin capital letter S
T 84 Latin capital letter T
U 85 Latin capital letter U
V 86 Latin capital letter V
W 87 Latin capital letter W
X 88 Latin capital letter X
Y 89 Latin capital letter Y
Z 90 Latin capital letter Z
[ 91 Left square bracket
\ 92 Reverse solidus
] 93 Right square bracket
^ 94 Circumflex accent
_ 95 Low line
` 96 Grave accent
a 97 Latin small letter a
b 98 Latin small letter b
c 99 Latin small letter c
d 100 Latin small letter d
e 101 Latin small letter e
f 102 Latin small letter f
g 103 Latin small letter g
h 104 Latin small letter h
i 105 Latin small letter i
j 106 Latin small letter j
k 107 Latin small letter k
l 108 Latin small letter l
m 109 Latin small letter m
n 110 Latin small letter n
o 111 Latin small letter o
p 112 Latin small letter p
q 113 Latin small letter q
r 114 Latin small letter r
s 115 Latin small letter s
t 116 Latin small letter t
u 117 Latin small letter u
v 118 Latin small letter v
w 119 Latin small letter w
x 120 Latin small letter x
y 121 Latin small letter y
z 122 Latin small letter z
{ 123 left curly bracket
| 124 Vertical line
} 125 Right curly bracket
~ 126 Tilde
127 (not used)
? 128 Euro sign Currency Symbols
? 129 (not used)
? 130 Single low-9 quotation mark General Punctuation
? 131 Latin small letter f with hook Latin Extended-B
? 132 Double low-9 quotation mark General Punctuation
? 133 Horizontal ellipsis General Punctuation
? 134 Dagger General Punctuation
? 135 Double dagger General Punctuation
? 136 Modifier letter circumflex accent Spacing Modifier Letters
? 137 Per mille sign General Punctuation
? 138 Latin capital letter S with caron Latin Extended-A
? 139 Single left-pointing angle quotation mark General Punctuation
? 140 Latin capital ligature OE Latin Extended-A
? 141 (not used)
? 142 Latin capital letter Z with caron Latin Extended-A
? 143 (not used)
? 144 (not used)
? 145 Left single quotation mark General Punctuation
? 146 Right single quotation mark General Punctuation
? 147 Left double quotation mark General Punctuation
? 148 Right double quotation mark General Punctuation
? 149 Bullet General Punctuation
? 150 En dash General Punctuation
? 151 Em dash General Punctuation
? 152 Small tilde Spacing Modifier Letters
? 153 Trade mark sign Letterlike Symbols
? 154 Latin small letter s with caron Latin Extended-A
? 155 Single right-pointing angle quotation mark General Punctuation
? 156 Latin small ligature oe Latin Extended-A
? 157 (not used)
? 158 Latin small letter z with caron Latin Extended-A
? 159 Latin capital letter Y with diaeresis Latin Extended-A
160 No-break space
? 161 Inverted exclamation mark
? 162 Cent sign
? 163 Pound sign
? 164 Currency sign
? 165 Yen sign
? 166 Broken bar
? 167 Section sign
? 168 Diaeresis
? 169 Copyright sign
? 170 Feminine ordinal indicator
? 171 Left-pointing double angle quotation mark
? 172 Not sign
? 173 Soft hyphen
? 174 Registered sign
? 175 Macron
? 176 Degree sign
? 177 Plus-minus sign
? 178 Superscript two
? 179 Superscript three
? 180 Acute accent
? 181 Micro sign
? 182 Pilcrow sign
? 183 Middle dot
? 184 Cedilla
? 185 Superscript one
? 186 Masculine ordinal indicator
? 187 Right-pointing double angle quotation mark
? 188 Vulgar fraction one quarter
? 189 Vulgar fraction one half
? 190 Vulgar fraction three quarters
? 191 Inverted question mark
? 192 Latin capital letter A with grave
? 193 Latin capital letter A with acute
? 194 Latin capital letter A with circumflex
? 195 Latin capital letter A with tilde
? 196 Latin capital letter A with diaeresis
? 197 Latin capital letter A with ring above
? 198 Latin capital letter AE
? 199 Latin capital letter C with cedilla
? 200 Latin capital letter E with grave
? 201 Latin capital letter E with acute
? 202 Latin capital letter E with circumflex
? 203 Latin capital letter E with diaeresis
? 204 Latin capital letter I with grave
? 205 Latin capital letter I with acute
? 206 Latin capital letter I with circumflex
? 207 Latin capital letter I with diaeresis
? 208 Latin capital letter Eth
? 209 Latin capital letter N with tilde
? 210 Latin capital letter O with grave
? 211 Latin capital letter O with acute
? 212 Latin capital letter O with circumflex
? 213 Latin capital letter O with tilde
? 214 Latin capital letter O with diaeresis
? 215 Multiplication sign
? 216 Latin capital letter O with stroke
? 217 Latin capital letter U with grave
? 218 Latin capital letter U with acute
? 219 Latin capital letter U with circumflex
? 220 Latin capital letter U with diaeresis
? 221 Latin capital letter Y with acute
? 222 Latin capital letter Thorn
? 223 Latin small letter sharp s
? 224 Latin small letter a with grave
? 225 Latin small letter a with acute
? 226 Latin small letter a with circumflex
? 227 Latin small letter a with tilde
? 228 Latin small letter a with diaeresis
? 229 Latin small letter a with ring above
? 230 Latin small letter ae
? 231 Latin small letter c with cedilla
? 232 Latin small letter e with grave
? 233 Latin small letter e with acute
? 234 Latin small letter e with circumflex
? 235 Latin small letter e with diaeresis
? 236 Latin small letter i with grave
? 237 Latin small letter i with acute
? 238 Latin small letter i with circumflex
? 239 Latin small letter i with diaeresis
? 240 Latin small letter eth
? 241 Latin small letter n with tilde
? 242 Latin small letter o with grave
? 243 Latin small letter o with acute
? 244 Latin small letter o with circumflex
? 245 Latin small letter o with tilde
? 246 Latin small letter o with diaeresis
? 247 Division sign
? 248 Latin small letter o with stroke
? 249 Latin small letter u with grave
? 250 Latin small letter u with acute
? 251 Latin small letter with circumflex
? 252 Latin small letter u with diaeresis
? 253 Latin small letter y with acute
? 254 Latin small letter thorn
? 255 Latin small letter y with diaeresis

說明中寫到 ShortString 只能放255個字元，String(預設情況下)與AnsiString是相同的，但是長度是不限的，WideStrings也是長度不限。

字串操作運算元
+ Concatenates two strings together(結合兩個字串)
= Compares for string equality(比對兩個字串)
< Is one string lower in sequence than another(字串的順序小於另一個字串，我猜是Ansi排序)
<= Is one string lower or equal in sequence with another(字串的順序小於或等於另一個字串)
> Is one string greater in sequence than another(字串的順序大於另一個字串，我猜是Ansi排序)
>= Is one string greater or equal in sequence with another(字串的順序大於或等於另一個字串)
<> Compares for string inequality(兩字串不相等)

範例
var
myString : string;
begin
myString := ‘Hello ‘ + ‘World’; // String concatenation

if ‘ABC’ = ‘abc’ // Equality 不等於所以 false，所以 ABC=abc是不會show出來的
then ShowMessage(‘ABC = abc’);
if ‘ABC’ = ‘ABC’ // Equality 兩個字串相等所以 true
then ShowMessage(‘ABC = ABC’);
if ‘ABC’ < ‘abc’ // Less than 小寫在ansi中比大寫早出現所以 ture
then ShowMessage(‘ABC < abc’);
if ‘ABC’ <= ‘abc’ // Less than or equal 同上
then ShowMessage(‘ABC <= abc’);
if ‘ABC’ > ‘abc’ // Greater than 剛好相反所以 false
then ShowMessage(‘ABC > abc’);
if ‘ABC’ >= ‘abc’ // Greater than or equal 同上
then ShowMessage(‘ABC >= abc’);
if ‘ABC’ <> ‘abc’ // Inequality 兩字串不相同所以 true
then ShowMessage(‘ABC <> abc’);
end;

輸出結果
ABC = ABC
ABC < abc
ABC <= abc
ABC <> abc

字串操作
複製
Source := ‘12345678’;
Target := Copy(Source, 3, 4); // Target now = ‘3456’ 從第3個字起copy 4個字元
插入
Target := ‘12345678’;
Insert(‘-+-‘, Target, 3); // Target now = ’12-+-345678′ 從字中Target中的第3個字元開始插入
刪除
Target := ‘12345678’;
Delete(Target, 3, 4); // Target now = ‘1278’ 從字串Target第三個字元起刪除4個字元
重複
Target := StringOfChar(‘S’, 5); // Target now = ‘SSSSS’ 將字串指定成5個重複的’S’
取代
// Target set to ‘This is THE way to live THE big life’ 取代的值會變成 This is a way to libe a big life.
Target := StringReplace(before, ‘ a ‘, ‘ THE ‘,
[rfReplaceAll, rfIgnoreCase]); //後面兩個參數是指全部取代還是不分大小寫取代
字串操作涵數
AnsiLeftStr Returns leftmost characters of a string
AnsiMidStr Returns middle characters of a string
AnsiRightStr Returns rightmost characters of a string
AnsiStartsStr Does a string start with a substring?
AnsiContainsStr Does a string contain another?
AnsiEndsStr Does a string end with a substring?
AnsiIndexStr Check substring list against a string
AnsiMatchStr Check substring list against a string
AnsiReverseString Reverses characters in a string
AnsiReplacStr Replaces all substring occurences
DupeString Repeats a substring n times
StrScan Scans a string for a specific character
StuffString Replaces part of a string text
Trim Removes leading and trailing white space
TrimLeft Removes leading white space
TrimRight Removes trailing white space

從數字轉字串
CurrToStrF Convert a currency value to a string with formatting
DateTimeToStr Converts TDateTime date and time values to a string
DateTimeToString Rich formatting of a TDateTime variable into a string
DateToStr Converts a TDateTime date value to a string
FloatToStr Convert a floating point value to a string
FloatToStrF Convert a floating point value to a string with formatting
Format Rich formatting of numbers and text into a string
FormatCurr Rich formatting of a currency value into a string
FormatDateTime Rich formatting of a TDateTime variable into a string
FormatFloat Rich formatting of a floating point number into a string
IntToHex Convert an Integer into a hexadecimal string
IntToStr Convert an integer into a string
Str Converts an integer or floating point number to a string

從字串轉數值
StringToWideChar Converts a string into a WideChar 0 terminated buffer
StrToCurr Convert a number string into a currency value
StrToDate Converts a date string into a TDateTime value
StrToDateTime Converts a date+time string into a TDateTime value
StrToFloat Convert a number string into a floating point value
StrToInt Convert an integer string into an Integer value
StrToInt64 Convert an integer string into an Int64 value
StrToInt64Def Convert a string into an Int64 value with default
StrToIntDef Convert a string into an Integer value with default
StrToTime Converts a time string into a TDateTime value
Val Converts number strings to integer and floating point values