How to capitalize first letter of first word in a sentence?

Question

I am trying to write a function to clean up user input.

I am not trying to make it perfect. I would rather have a few names and acronyms in lowercase than a full paragraph in uppercase.

I think the function should use regular expressions but I'm pretty bad with those and I need some help.

If the following expressions are followed by a letter, I want to make that letter uppercase.

 "."
 ". " (followed by a space)
 "!"
 "! " (followed by a space)
 "?"
 "? " (followed by a space)

Even better, the function could add a space after ".", "!" and "?" if those are followed by a letter.

How this can be achieved?

Offering realistic sample input and desired output are vital parts of creating a [mcve]. — mickmackusa, Aug 13 '21 at 16:08

w35l3y · Accepted Answer · 2013-06-14T20:54:11.863

33

$output = preg_replace('/([.!?])\s*(\w)/e', "strtoupper('\\1 \\2')", ucfirst(strtolower($input)));

Since the modifier e is deprecated in PHP 5.5.0:

$output = preg_replace_callback('/([.!?])\s*(\w)/', function ($matches) {
    return strtoupper($matches[1] . ' ' . $matches[2]);
}, ucfirst(strtolower($input)));

edited Jun 14 '13 at 20:54

answered Mar 21 '11 at 21:10

w35l3y

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@w35l3y your code interest me... but How to do if my string is with some tags like that for example : `hello. this doesn' work !` ... ? can you improve your code please for this kind of case ? In fact, how to escape `` without delete them ? thank you :) – Zagloo Mar 31 '15 at 10:14
@Zagloo, in the case above, it is a requirement to have just 1 space independently of the current number of spaces. In your case, it is subject to a new question. Consider asking a new one and let me know. In short, I don't have good news for you because a `span` without any attribute is easy, but what about nested nodes with various attributes each? – w35l3y Mar 31 '15 at 18:10
@w35l3y Thx for your return ! I made a new post yesterday and someone found the solution here : http://stackoverflow.com/questions/29366592/php-improve-text-capitalization-function/29367216#29367216 ;o) – Zagloo Apr 01 '15 at 06:54
Hello. I don't understand the part `[.!?] `of the regular expression. Isn't the unescaped dot expected to match ANY character (including "!" and "?")? I think it should be escaped but this answer has been here a lot of time... – NeDark Aug 27 '16 at 23:30
@NeDark, in a `[]` block any character except `-^\]` is a literal. – w35l3y Aug 30 '16 at 20:23

score 3 · Answer 2 · answered Mar 21 '11 at 21:02

Here is the code that does as you wanted:

<?php

$str = "paste your code! below. codepad will run it. are you sure?ok";

//first we make everything lowercase, and 
//then make the first letter if the entire string capitalized
$str = ucfirst(strtolower($str));

//now capitalize every letter after a . ? and ! followed by space
$str = preg_replace_callback('/[.!?] .*?\w/', 
  create_function('$matches', 'return strtoupper($matches[0]);'), $str);

//print the result
echo $str . "\n";
?>

OUTPUT: Paste your code! Below. Codepad will run it. Are you sure?ok

you don't need anymore create_function :)( – dynamic Mar 21 '11 at 21:09 — dynamic, Mar 21 '11 at 21:09

score 1 · Answer 3 · answered Aug 25 '16 at 18:02

How about this? Without Regex.

$letters = array(
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
);
foreach ($letters as $letter) {
    $string = str_replace('. ' . $letter, '. ' . ucwords($letter), $string);
    $string = str_replace('? ' . $letter, '? ' . ucwords($letter), $string);
    $string = str_replace('! ' . $letter, '! ' . ucwords($letter), $string);
}

Worked fine for me.

score 1 · Answer 4 · edited Mar 21 '11 at 22:43

1

Separate string into arrays using ./!/? as delimeter. Loop through each string and use ucfirst(strtolower($currentString)), and then join them again into one string.

edited Mar 21 '11 at 22:43

David Thomas

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answered Mar 21 '11 at 20:57

chojnovsky

11
1

Interesting take. I'll give it a try. I was hoping to practice my regex a little but this could get the job done. Thank you. – Enkay Mar 21 '11 at 21:04

score 1 · Answer 5 · answered Mar 21 '11 at 21:08

1

This:

<?
$text = "abc. def! ghi? jkl.\n";
print $text;
$text = preg_replace("/([.!?]\s*\w)/e", "strtoupper('$1')", $text);
print $text;
?>

Output:
abc. def! ghi? jkl.
abc. Def! Ghi? Jkl.

Note that you do not have to escape .!? inside [].

answered Mar 21 '11 at 21:08

Damon

67,688
20
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score 0 · Answer 6 · answered Mar 21 '11 at 21:05

0

$output = preg_replace('/([\.!\?]\s?\w)/e', "strtoupper('$1')", $input)

answered Mar 21 '11 at 21:05

Sony Santos

5,435
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preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead – Sylar Apr 26 '21 at 12:17

score -2 · Answer 7 · edited Dec 17 '18 at 17:13

-2

$Tasks=["monday"=>"maths","tuesday"=>"physics","wednesday"=>"chemistry"];

foreach($Tasks as $task=>$subject){

     echo "<b>".ucwords($task)."</b> : ".ucwords($subject)."<br/>";
}

edited Dec 17 '18 at 17:13

Yuca

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answered Dec 17 '18 at 16:00

user10802142

1

How to capitalize first letter of first word in a sentence?

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