文章目录
29. 字符数组和字符串数组、文本操作常用函数
29.1 字符数组和字符串数组
Apple_char = 'Apple'; % 向量形式存储
class(Apple_char); % char
Apple_string = "Apple"; % 标量形式存储
class(Apple_string); % string
double(Apple_char); % 得到字符对应数字，65 112 112 108 101
size(Apple_char); % 1 5
length(Apple_char); % 5，返回行或列数最大值
Apple_char(2); % 'p'
size(Apple_string); % 1 1
length(Apple_string); % 1
Apple_string(1); % "Apple"
Apple_string{1}; % 'Apple',将字符串变为字符
Apple_string{1}(2); % 'p'
majors = ["English","History","Engineering"]; % majors = "English" "History" "Engineering"
majors_char = ['English','History','Engineering']; % majors_char = 'EnglishHistoryEngineering'
majors_char = char('English','History','Engineering');
% 3×11 char 数组
% 'English '
% 'History '
% 'Engineering'
''; % 0行0列
['','']; % 0行0列
["",""]; % 1行2列
29.2 文本操作常用函数
input('Enter some:','s'); % 输入字符为字符类型
repmat('a',4,3);
% 4×3 char 数组
% 'aaa'
% 'aaa'
% 'aaa'
% 'aaa'
['a' blanks(5) 'b']; % 'a b'
string('Apple'); % "Apple"
string([65 112 112 108 101]); % 1×5 string 数组,"65" "112" "112" "108" "101"
char([65 112 112 108 101]); % 'Apple'
string(char([65 112 112 108 101])); % "Apple"
"a" + "b"; % "ab"
['a' 'b']; % 'a b'
strcat('a','b',' ','c'); % 'abc'
strcat("a","b"," ","c"); % "ab c"
fprintf('%7.3f \n',pi); % 3.142
sent1 = sprintf('%7.3f \n',pi); % 用于将输出内容转发给其它变量
% ' 3.142
% '
a = 1;
title(sprintf('title is %d',a)); % 动态改变标题名
username = input('Please enter your name:','s');
id_no = input(sprintf('%s,enter your id #:',username)); % 用sprintf()转为字符，传入input函数
30. 删除字符,比较字符数组与字符串
30.1 删除字符
test_char = ' q a ';
deblank(test_char); % 删除后边的空格, ' q a'
strtrim(test_char); % 删除前后所有空格，'q a'
test_char = '-a-';
strip(test_char,'-'); % 第二个参数是要删除的符号，'a'
tets_str = "-a";
strip(test_str,'-'); % 第二个参数是要删除的符号，"a"
test_char = 'xxAxBx';
erase(test_char,'x'); % 第二个参数是要删除的字符，可以是多个，'AB'
erase(test_char,'xA'); % 'B'
tets_str = "xxAxBx";
erase(tets_str,'x'); % 第二个参数是要删除的字符，可以是多个，"AB"
erase(tets_str,'xA'); % "B"
lower('ABC'); % 'abc'
upper('abc'); % 'ABC'
30.2 比较字符数组与字符串
'abc' == 'acb'; % 长度必须相同，logical, 1 0 0
'abc' == 'acbd'; % 错误
strcmp('abc','acb'); % logical,0
strcmp('abc','acbd'); % logical,0
strcmp('abc','abc'); % logical,1
strncmp('abc','abcd',3); % 比较前3个字符,logical,1
strcmpi('abC','ABc'); % 不区分大小写，logical , 1
isequal('abc','abcd'); % logical,0
"abc" = "acb" ; % logical , 0
strcmp("abc","abcd"); % logical , 0
isequal("abc","abcd"); % logical, 0
['a','b']; % 'ab'
["a","b"]; % 1×2 string 数组,"a" "b"
{'a','b'}; % 1×2 cell 数组,{'a'} {'b'}
{"a","b"}; % 1×2 cell 数组,{["a"]} {["b"]}
strcmp(["a","b"],["a","c"]); % 1×2 logical 数组,1 0
isequal(["a","b"],["a","c"]); % 0
strcmp({'a','b'},{'a','c'}); % 1×2 logical 数组,1 0
isequal({'a','b'},{'a','c'}); % 0
31. 字符数组和字符串的搜索、替换，分割和合并，文本信息的判断与检测
31.1 字符数组和字符串的搜索、替换
strfind('abcd','d'); % 4,找到第二参数在第一个参数中的位置
strfind("abcde","bc"); % 2
strfind('abab','a'); % 1 3
strfind('abab','a','c'); % cbcb,用‘c'替换'a'
31.2 字符数组和字符串的统计
count('abab','a'); % 2, 'a'字符出现的次数
count('abab',''); % 6, 字符之间是一个''
count("abab",""); % 6
31.3 字符数组和字符串的分割
[word,rest] = strtok("Hello there"," "); % word = "Hello" rest = " there"
[word,rest] = strtok("Hello there"); % word = "Hello" rest = " there"
[word,rest] = strtok("Hello there","tl"); % 以t或l进行分割，谁先出现，就按谁分割。word = "He" rest = "llo there"
[word,rest] = strtok("Hello there","Y"); % word = "Hello there" rest = ""
31.4 字符数组和字符串的合并
strings(2,4); % 2行4列string类型数组
majors = ["a","b","c"];
upper(majors); % 大写,"A" "B" "C"
"I am " + majors; % 标量+向量，1×3 string 数组,"I am a" "I am b" "I am c"
degrees = ["d","e","f"];
majors + degrees; % 向量+向量，1×3 string 数组，"ad"
newsa = [majors;degrees];
% 2×3 string 数组
% "a" "b" "c"
% "d" "e" "f"
join(newsa); % 把每一行合并
% 2×1 string 数组
% "a b c"
% "d e f"
strjoin(newsa); % 把所有行合并，"a d b e c f"
31.5 文本信息的判断与检测
isletter('A'); % 判断字符，1
isletter('ab'); % 1 1
isspabe('a b'); % 判断空格，0 1 0
ischar('abc'); % 判断字符类型,1
isstring("abc"); % 判断字符串类型,1
isstring(["ab","cb"]); % 1
isStringScalar("1"); % 判断是否是标量，1
isStringScalar(["1","b"]); % 0
contains("hello","e"); % 是否包含“e", 1
contains(["ab","ac","et"],"a"); % 1 1 0
contains("hello",""); % 是否空白字符存在，1
startsWith(["ab","ac","et"],"a"); % 是否以"a"开头， 1 1 0
endsWith(["ab","ac","et"],"a"); % 是否以"a"结尾， 0 0 0
32. 文本类型和数值类型的转换
num = 38;
int2str(num); % '38'
int2str(pi); % '3'
num2str(pi); % '3.1456'
int2str(2:5): % '2 3 4 5'
num2str(2:5); % '2 3 4 5'
num2str(3.456789,3); % 保留三位数, '3.46'
num2str(3.456789,'%06.2f'); % '003.46'
str2double('1.23'); % 只能识别一个数字，1.23
str2double('123 456'); % NaN
str2double(["123","456"]); % 123 456
str2num('1.23'); % 1.23
str2num('123 456'); % 能识别多个数字，123 456
str2num(["123","456"]);% 错误，输入必须为字符向量或字符串标量
str2num(['123','456']); % 123456
char(92); % '\'
string(92); % "92"
char(54:55); % '67'
string(54:55); % "54" "55"
