PHP Learning Small Notes

PHP 's four marker styles

1.XML Style

<?php

echo "XML style ";

?>

2. Script Style

<scriptlanguage= "PHP" >

echo ' scripting style ';

</script>

3. Short style

<?echo ' short style ';? >

4.ASP Style

<%

Echo ' ASP style ';

%>

PHP three style of annotation

1. Single-line comment //

2.Multiline Comment /*...*/ ( nested operation not allowed )

3.Shell style Comment #

single and double quotation marks differences in PHP

Single quotes: What you see is what you get

double quotes: content can be interpreted and replaced

<?php

$test = "PHP";

$str = "I like $test";

$str 1= ' I like $test ';

Echo $str;

echo $str 1;

?>

The result is

ILike PHP

ILike $test

PHP string Interception Considerations

When the substr () function intercepts a Chinese string, if an odd number occurs in the truncated string, it may cause the intercepted characters to be garbled because a Chinese character consists of two bytes.

PHP Comparison String

1. String comparisons by Byte

strcmp () case-sensitive

STRCASECMP () is case insensitive

equals is returned 0

2, natural sorting method for string comparison

STRNATCMP () returns equal to 0; Case Sensitive

STRNATCASECMP () is case insensitive

3, specify the location from the source string to start the comparison

STRNCMP () case-sensitive

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PHP Learning Small Notes