[英]Remove extra whitespace from a string in C
I have this string我有这个字符串
"go for goa"
and the output should be并且输出应该是
"go for goa"
I want to remove the extra spaces.我想删除多余的空格。 That means two or more consecutive spaces should be replaced with one space.这意味着两个或多个连续空格应替换为一个空格。 I want to do it using an in place algorithm.我想使用就地算法来做到这一点。
Below is the code I tried but it doesn't work:以下是我尝试过但不起作用的代码:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Function to remove spaces in an string array */
char *removeSpaces(char *str) {
int ip_ind = 1;
/* In place removal of duplicate spaces*/
while(*(str + ip_ind)) {
if ((*(str + ip_ind) == *(str + ip_ind - 1)) && (*(str + ip_ind)==' ')) {
*(str_ip_ind-1)= *(str + ip_ind);
}
ip_ind++;
}
/* After above step add end of string*/
*(str + ip_ind) = '\0';
return str;
}
/* Driver program to test removeSpaces */
int main() {
char str[] = "go for go";
printf("%s", removeSpaces(str));
getchar();
return 0;
}
Most solutions seem needlessly complicated:大多数解决方案似乎不必要地复杂:
#include <ctype.h>
#include <stdio.h>
void strip_extra_spaces(char* str) {
int i, x;
for(i=x=0; str[i]; ++i)
if(!isspace(str[i]) || (i > 0 && !isspace(str[i-1])))
str[x++] = str[i];
str[x] = '\0';
}
int main(int argc, char* argv[]) {
char str[] = " If you gaze into the abyss, the abyss gazes also into you. ";
strip_extra_spaces(str);
printf("%s\n",str);
return 0;
}
I can't even tell what your function is trying to do.我什至无法判断您的功能正在尝试做什么。 For one thing, the first time through, that -1 will access before the start of the string.一方面,第一次通过,-1 将在字符串开始之前访问。 Try something like:尝试类似:
char *removeSpaces(char *str) {
char *inp = str, *outp = str;
int prevSpace = 0;
while (*inp) {
if (isspace(*inp)) {
if (!prevSpace) {
*outp++ = ' ';
prevSpace = 1;
}
} else {
*outp++ = *inp;
prevSpace = 0;
}
++inp;
}
*outp = '\0';
return str;
}
You aren''t checking for a space.. You are checking for a tab.您不是在检查空格.. 您是在检查选项卡。 Replace \\t with (I mean space..)将 \\t 替换为(我的意思是空格..)
Your if
condition doesn't work.您的if
条件不起作用。 I will show you my code.我会告诉你我的代码。 It is similar to yours, by just using two pointers: back
and front
.它与您的类似,只需使用两个指针: back
和front
。
If front
is not a space, or front
is a space but back
is not a space, you need to copy front
to back+1
.如果front
不是空格,或者front
是空格而back
不是空格,则需要将front
复制到back+1
。
char *removeSpaces(char *str)
{
if (*str == '\0') return str;
char *back = str;
char *front = str + 1;
/* In place removal of duplicate spaces*/
while(*front != '\0')
{
if (*front != ' ' || *back != ' ') // highlight
*(++back) = *front;
front++;
}
/* After above step add end of string*/
*(back + 1) = '\0';
return str;
}
Hope this may help you.希望这可以帮助你。
Would tell best answer left space @end ?会告诉最佳答案留下空间@end 吗? Here simple translation to JS:这里简单翻译成JS:
function strip_extra_spaces(str) { var i, x; for (i = x = 0; str[i]; ++i) if (!isspace(str[i]) || (i > 0 && !isspace(str[i - 1]))) str[x++] = str[i]; str[x] = '\\0'; return str; } str = " If you gaze into the abyss, the abyss gazes also into you. "; console.log( strip_extra_spaces(str.split("")) .join("") .replace(/\\0.+/g, "") .replace(/\\s/g, '☐') ) function isspace(c) { return c == ' '; }
Looking for something similar in C# to compare multiple strings and made this - inspired by recursion.ninja's and similar C# answer to Efficient way to remove ALL whitespace from String?在 C# 中寻找类似的东西来比较多个字符串并做了这个 - 灵感来自 recursion.ninja 和类似的 C# 对Efficient way to remove all whitespace from String 的回答? - also problematic - removed spaces completely. - 也有问题 - 完全删除了空格。
public static string TrimAllWithInplaceCharArray(string a) {
var len = a.Length;
var srcA = a.ToCharArray();
int dstIdxA = 0;
int planSpace = 0;
for (int i = 0; i < len; ++i) {
var ch = srcA[i];
switch (ch) {
case '\u0020': case '\u00A0': case '\u1680': case '\u2000': case '\u2001':
case '\u2002': case '\u2003': case '\u2004': case '\u2005': case '\u2006':
case '\u2007': case '\u2008': case '\u2009': case '\u200A': case '\u202F':
case '\u205F': case '\u3000': case '\u2028': case '\u2029': case '\u0009':
case '\u000A': case '\u000B': case '\u000C': case '\u000D': case '\u0085':
if (planSpace == 1) planSpace = 2;
break;
default:
if (planSpace > 1)
{
srcA[dstIdxA++] = ' ';
}
srcA[dstIdxA++] = ch;
planSpace = 1;
break;
}
}
return new string(srcA, 0, dstIdxA);
}
The problem:问题:
ip_ind
, you must inc, only when deletion is not done, because when deletion is done, that scenario will be equal to incremented.每次你不能增加ip_ind
,你必须增加,只有当删除没有完成时,因为当删除完成时,那个场景将等于增加。""
, to avoid it, add a check parameter as below (Method 1) or else start from ip_ind
from 0 as in (Method 2).您的场景将因""
而失败,为了避免它,添加一个检查参数如下(方法 1),或者从ip_ind
开始,从 0 开始(方法 2)。 (Thanks to @Lee Daniel Crocker) (感谢@Lee Daniel Crocker) Solution:解决方案:
You could try like this.,你可以这样试试
Method 1 : ip_ind starts from one.方法一:ip_ind从1开始。
/* Function to remove spaces in an string array */
char *removeSpaces(char *str)
{
int ip_ind = 1;
char *ptr;
if(*str)
return str;
/* In place removal of duplicate spaces*/
while(*(str + ip_ind))
{
if ( (*(str + ip_ind) == *(str + ip_ind - 1)) && (*(str + ip_ind)==' ') )
{
ptr = str + ip_ind;
//Functionality for removal of spaces.
do{
*(ptr-1) = *ptr;
}while(*ptr++ != '\0');
}
else //Inc only if deletion is not done.
ip_ind++;
}
/* After above step add end of string*/
*(str + ip_ind) = '\0';
return str;
}
Method 2 : ip_ind starts from zero.方法二:ip_ind 从零开始。
char *removeSpaces(char *str)
{
int ip_ind = 0;
char *ptr;
/* In place removal of duplicate spaces*/
while(*(str + ip_ind))
{
if ( (*(str + ip_ind) == *(str + ip_ind + 1)) && (*(str + ip_ind)==' ') )
{
ptr = str + ip_ind+1;
do{
*(ptr-1) = *ptr;
}while(*ptr++ != '\0');
}
else
ip_ind++;
}
/* After above step add end of string*/
*(str + ip_ind) = '\0';
return str;
}
There you go:你去吧:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Function to remove spaces in an string array */
char *removeSpaces(char *str) {
int ip_ind = 0;
while (*(str+ip_ind) != 0) {
if (*(str + ip_ind++) == 32) {
if (*(str + ip_ind) == 32) {
int x=ip_ind;
while (*(str + x +1) != 0) {
*(str + x)= *(str + 1 + x++);
}
*(str + x)= 0;
--ip_ind;
}
}
}
return str;
}
/* Driver program to test removeSpaces */
int main() {
char str[] = "go for go";
printf("%s\n", str);
printf("%s\n", removeSpaces(str));
char str2[] = "go for go for go";
printf("%s\n", str2);
printf("%s\n", removeSpaces(str2));
return 0;
}
Output:输出:
dda$ ./a.out
go for go
go for go
go for go for go
go for go for go
dda$
Simple one for You简单给你
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char a[100];
int i,t,k;
scanf("%[^\n]s",a);
t=strlen(a);
for(i=0;i<t;)
{
if((a[i]==' ')&&(a[i+1]==' '))
{
for(k=i+1;k<t;k++)
{
a[k]=a[k+1];
}
t=t-1;
}
else
i++;
}
printf("%s",a);
return 0;
}
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