erlang 中的 string 应用

string 的一些功能操作,这些可能和wxTextCtrl 控件配合使用的比较多

(0)目的:["a","b","c","d"] -> "abcd"
L1 = ["a","b","c","d"],
binary_to_list(list_to_binary(L1)).
"abcd"
(1)求字符串的长度
string:len("abcdefabc"). -> 9
判断两个字符串是否相等
string:equal("abc","abc").
true
(2)两个字符串组合为一个字符串
string:concat("abc","def").
"abcdef"
(3)求第一个或者最后一个某字符在字符串中的顺序,不存在为0,
以1为起始坐标
string:chr("abdcdef",$d).
3
string:rchr("abdcdef",$d).
5
(4)求某个子字符串在字符串中出现的第一或者最后位置
string:str("hehe haha haha","haha").
6
string:rstr("hehe haha haha","haha").
11
(5)截取字符串 以及 从起始到的若干个字符串
string:substr("Hello World",4).
"lo World"
string:substr("Hello World",4,5).
"lo Wo"

(6)分割字符串,但是用于分割的源字符串中的字符就不出现了
string:tokens("asdhfgjjdttfg","df").
["as","h","gjj","tt","g"]
(7)用特定字符连接字符串
string:join(["aaa","bbb","ccc"],"@").
"aaa@bbb@ccc"
(8) 若干字符连接成一个字符串
string:chars($a,5).
"aaaaa"
string:chars($d, 10, "ee").
"ddddddddddee"
(9) 若干字符串连接成一个字符串,
string:copies("as",5).
"asasasasas"
若干个字符串连接成一个字符串,并以某个字符串结尾
string:words("aaa bbb ccc").
3
(10)字符串中有几个隔开的字(word)
string:words("abcbchdbjfb",$b).
4
(11) 用字符隔开后取第几个字符串
string:sub_word("abcbchdbjfb",3,$b).
"chd"

(12)去掉字符串某方向的某一些字符,如左,右,两边,默认去掉的是空格
默认去掉的是两边的
string:strip(" aaa ").
"aaa"
string:strip("...aaa..",both,$.).
"aaa"
string:strip("...aaa..",left,$.).
"aaa.."
string:strip("...aaa..",right,$.).
"...aaa"

(13)截取前面几个字符
截取前面几个字符,如果不足,以某个字符补齐,
还可以是右边或者中间
string:centre("HelloHello", 5).
"lloHe"
string:centre("HelloHello", 20).
" HelloHello "
string:centre("HelloHello", 20, $.).
".....HelloHello....."
(14)
所有字符转为大写或者所有字符转为小写
string:to_lower("AAA123").
"aaa123"
string:to_upper("bbb123").
"BBB123"

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(15)里面有string:span 和 string:rpan 是匹配的还没有看明白
(16)string转为 integer
list_to_integer("11111").
11111
list_to_integer("11111aaa").
** exception error: bad argument
in function list_to_integer/1
called as list_to_integer("11111aaa")
string:to_integer("1111aaa").
{1111,"aaa"}
{I1,Is} = string:to_integer("33+22"),
{I2,[]} = string:to_integer(Is),
I1-I2.
11
(17)string转为 float
{F1,Fs} = string:to_float("1.0-1.0e-1"),
{F2,[]} = string:to_float(Fs),
F1+F2.
0.9
string:to_float("3/2=1.5").
{error,no_float}
string:to_float("-1.5eX").
{-1.5,"eX"}
(18)
98> float_to_list(2.3333, [{decimals, 2}]).
"2.33"
float_to_list(2.333).
"2.33300000000000018474e+00"
list_to_float("2.3333").
2.3333

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参考:
http://www.erlang.org/doc/man/string.html
http://abin888.blog.sohu.com/236274578.html
http://blog.csdn.net/zgl_dm/article/details/5967156