PHP字串word末字元實現大小寫互換的方法，字串大小寫_PHP教程

PHP字串word末字元實現大小寫互換的方法，字串大小寫

本文執行個體講述了PHP字串word末字元實現大小寫互換的方法。分享給大家供大家參考。具體實現方法如下：

一、要求：
給出一個字串如 “A journey of, a thousand 'miles' must can't \"begin\" with a single step.” ，通過 PHP 程式處理變成 “a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP.”

這裡需要注意：

1、每個單詞最後的字元如果是大寫就變成小寫，如果是小寫就變成大寫。
2、需要考慮類似 can't 這種形式的轉換。
3、標點符號（只考慮 , ' " . ;）不用變化。

二、參考演算法如下：

複製代碼 代碼如下:<?php
function convertLastChar($str) {
$markArr = array(", ", "' ", "\" ", ". ", "; ");
$ret = "";
for ($i = 0, $j = strlen($str); $i < $j; $i++) {
if ($i < $j - 2) {
$afterStr = $str{$i + 1} . $str{$i + 2};
} else if ($i < $j - 1) {
$afterStr = $str{$i + 1} . " ";
}
if (in_array($afterStr, $markArr)
|| $i == $j - 1
|| $str{$i + 1} == " ") {
$ret .= strtoupper($str{$i}) === $str{$i}
? strtolower($str{$i})
: strtoupper($str{$i});
} else {
$ret .= $str{$i};
}
}
return $ret;
}
?>

測試代碼如下：
複製代碼 代碼如下:<?php

//test
$str1 = "A journey of, a thousand 'miles' must can't \"begin\" with a single step.";
$str2 = "A journey of, a thousand 'miles' must can't \"begin\" with a single step. ";
$str3 = "A journey of, a thousand 'miles' must can't \"begin\" with a single step. a ";
$str4 = "A journey of, a thousand 'miles' must can't \"begin\" with a single step. a B";
$str5 = "A journey of, a thousand 'miles' must can't \"begin\" with a single step. a b'";
$str6 = "A journey of, a thousand 'miles' must can't \"begin\" with a single step. a B\"";

echo "source:
" . $str1 . "
result:
" . convertLastChar($str1) . "

";
echo "source:
" . $str2 . "
result:
" . convertLastChar($str2) . "

";
echo "source:
" . $str3 . "
result:
" . convertLastChar($str3) . "

";
echo "source:
" . $str4 . "
result:
" . convertLastChar($str4) . "

";
echo "source:
" . $str5 . "
result:
" . convertLastChar($str5) . "

";
echo "source:
" . $str6 . "
result:
" . convertLastChar($str6) . "

";
?>

運行結果如下：
複製代碼 代碼如下:source:
A journey of, a thousand 'miles' must can't "begin" with a single step.
result:
a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP.

source:
A journey of, a thousand 'miles' must can't "begin" with a single step.
result:
a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP.

source:
A journey of, a thousand 'miles' must can't "begin" with a single step. a
result:
a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP. A

source:
A journey of, a thousand 'miles' must can't "begin" with a single step. a B
result:
a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP. A b

source:
A journey of, a thousand 'miles' must can't "begin" with a single step. a b'
result:
a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP. A B'

source:
A journey of, a thousand 'miles' must can't "begin" with a single step. a B"
result:
a journeY oF, A thousanD 'mileS' musT can'T "begiN" witH A singlE steP. A b"

希望本文所述對大家的PHP程式設計有所協助。

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