C语言 从字符串中删除空格和特殊字符
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Removing spaces and special characters from string
提问by dertzi
How do you remove spaces andspecial characters from a string?
如何从字符串中删除空格和特殊字符？
I couldn't find a single answer while googling. There were a lot related to other languages, but not C. Most of them mentioned the use of regex, which isn't C standard (?).
谷歌搜索时我找不到一个答案。有很多与其他语言相关，但与 C 无关。他们中的大多数都提到了正则表达式的使用，这不是 C 标准（？）。
Removing a simple space is easy:
删除一个简单的空间很容易：
char str[50] = "Remove The Spaces!!";
Then a simple loop with a if-statement:
然后是一个带有 if 语句的简单循环：
if (str[i] != ' ');
Output would be:
输出将是：
RemoveTheSpaces!!
What do I add to the if-statement so it would recognize special characters and remove them?
我要在 if 语句中添加什么才能识别特殊字符并删除它们？
My definition of special characters:
我对特殊字符的定义：
Characters not included in this list:
A-Z a-z 0-9
回答by
This is probably not the most efficient way of achieving this but it will get the job done fairly fast.
这可能不是实现这一目标的最有效方法，但它可以相当快地完成工作。
Note: this code does require you to include <string.h>and <ctype.h>
注意：此代码确实需要您包含<string.h>和<ctype.h>
char str[50] = "Remove The Spaces!!";
char strStripped[50];
int i = 0, c = 0; /*I'm assuming you're not using C99+*/
for(; i < strlen(str); i++)
{
if (isalnum(str[i]))
{
strStripped[c] = str[i];
c++;
}
}
strStripped[c] = 'char ordinary[CHAR_MAX] = {
['A']=1,['B']=1,['C']=1,['D']=1,['E']=1,['F']=1,['G']=1,['H']=1,['I']=1,
['J']=1,['K']=1,['L']=1,['M']=1,['N']=1,['O']=1,['P']=1,['Q']=1,['R']=1,
['S']=1,['T']=1,['U']=1,['V']=1,['W']=1,['X']=1,['Y']=1,['Z']=1,
['a']=1,['b']=1,['c']=1,['d']=1,['e']=1,['f']=1,['g']=1,['h']=1,['i']=1,
['j']=1,['k']=1,['l']=1,['m']=1,['n']=1,['o']=1,['p']=1,['q']=1,['r']=1,
['s']=1,['t']=1,['u']=1,['v']=1,['w']=1,['x']=1,['y']=1,['z']=1,
['0']=1,['1']=1,['2']=1,['3']=1,['4']=1,['5']=1,['6']=1,['7']=1,['8']=1,
['9']=1,
};
int is_special (int c) {
if (c < 0) return 1;
if (c >= CHAR_MAX) return 1;
return !ordinary[c];
}
void remove_spaces_and_specials_in_place (char *str) {
if (str) {
char *p = str;
for (; *str; ++str) {
if (!is_special(*str)) *p++ = *str;
}
*p = '#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
static void my_strip(char *data)
{
unsigned long i = 0; /* Scanning index */
unsigned long x = 0; /* Write back index */
char c;
/*
* Store every next character in `c` and make sure it is not '#include <stdio.h>
#include <string.h>
main()
{
int i=0, j=0;
char c;
char buff[255] = "Remove The Spaces!!";
for(; c=buff[i]=buff[j]; j++){
if(c>='A' && c<='Z' || c>='a' && c<='z' || c>='0' && c<='9'){
i++;
}
}
printf("char buff[255] = \"%s\"\n", buff);
}
'
* because 'include < stdio.h >
int main()
{
char a[100];
int i;
printf("Enter the character : ");
gets(a);
for (i = 0; a[i] != '0:48, 9:57
A:65, Z:90
a:97, z:122
'; i++) {
if ((a[i] >= 'a' && a[i] <= 'z') || (a[i] >= 'A' && a[i] <= 'Z')
|| (a[i] - 48 >= 0 && a[i] - 48 <= 9)) {
printf("%c", a[i]);
} else {
continue;
}
}
return 0;
}
' indicates the end of string, and we don't want
* to read past the end not to trigger undefined behavior.
* Then increment "scanning" index so that next time we read the
* next character.
*/
while ((c = data[i++]) != 'char str[50] = "Remove The Spaces!!";
int i =0;
for(; i<strlen(str); i++)
{
if(str[i]>=48 && str[i]<=57 || str[i]>=65 && str[i]<=90 || str[i]>=97 && str[i]<=122)
//This is equivalent to
//if(str[i]>='0' && str[i]<='9' || str[i]>='A' && str[i]<='Z' || str[i]>='a' && str[i]<='z')
printf("alphaNumeric:%c\n", str[i]);
else
{
printf("special:%c\n", str[i]);
//remove that
}
}
') {
/* Check if character is either alphabetic or numeric. */
if (isalnum(c)) {
/*
* OK, this is what we need. Write it back.
* Note that `x` will always be either the same as `i`
* or less. After writing, increment `x` so that next
* time we do not overwrite the previous result.
*/
data[x++] = c;
}
/* else — this is something we don't need — so we don't increment the
`x` while `i` is incremented. */
}
/* After all is done, ensure we terminate the string with 'if (str[i] != ' ');
'. */
data[x] = 'If ( !('a' <= str[i] && 'z' >= str[i]) &&
!('A' <= str[i] && 'Z' >= str[i]) &&
!('0' <= str[i] && '9' >= str[i])) then ignore character.
';
}
int main()
{
/* This is array we will be operating on. */
char data[512];
/* Ask your customer for a string. */
printf("Please enter a string: ");
if (fgets(data, sizeof(data), stdin) == NULL) {
/* Something unexpected happened. */
return EXIT_FAILURE;
}
/* Show the customer what we read (just in case :-)) */
printf("You have entered: %s", data);
/*
* Call the magic function that removes everything and leaves
* only alphabetic and numberic characters.
*/
my_strip(data);
/*
* Print the end result. Note that newline (\n) is there
* when we read the string
*/
printf("Stripped string: %s\n", data);
/* Our job is done! */
return EXIT_SUCCESS;
}
';
}
}
';
回答by jxh
This is just a silly suggestion.
这只是一个愚蠢的建议。
##代码##回答by jxh
There are millions of different ways this can be done. Here is just one example that is not using any additional storage and performs the removal of unneeded characters "in-place":
有数百万种不同的方法可以做到这一点。这只是一个不使用任何额外存储并“就地”删除不需要的字符的示例：
##代码##I put a lot of comments in there so hopefully the code doesn't need explanation. Hope it helps. Good Luck!
我在那里放了很多注释，所以希望代码不需要解释。希望能帮助到你。祝你好运！
回答by Kelton Santos
回答by Joseph watson
回答by bitmapdata.com
This is Ascii Code Range
这是 Ascii 代码范围
Char:Dec
Char:Dec
try this:
尝试这个：
##代码##回答by George Mitchell
Using your if statement:
使用你的 if 语句：
##代码##With a little logic (the characters have to be in the range a-z or A-Z or 0-9:
有点逻辑（字符必须在 az 或 AZ 或 0-9 范围内：
##代码##