Strings

Question 1

Returns a string with backslashes in front of the specified characters

Answer 1

addcslashes(string,characters)
---------------
EXAMPLE:
$str = addcslashes("Hello World!","W");
echo($str); 

OUTPUT:
Hello \World!

Question 2

Returns a string with backslashes in front of predefined characters

Answer 2

addslashes(string)
---------------
EXAMPLE:
$str = addslashes('What does "yolo" mean?');
echo($str); 

OUTPUT:
What does "yolo" mean?

Question 3

Converts a string of ASCII characters to hexadecimal values

Answer 3

bin2hex(string)
---------------
EXAMPLE:
$str = bin2hex("Hello World!");
echo($str);

OUTPUT:
48656c6c6f20576f726c6421

Question 4

Removes whitespace or other characters from the right end of a string

Answer 4

chop(string,charlist)
---------------
EXAMPLE:
$str = "Hello World!";
echo $str . "<br>";
echo chop($str,"World!");

OUTPUT:
Hello World!
Hello

Question 5

Returns a character from a specified ASCII value

Answer 5

chr(ascii)
---------------
EXAMPLE:
echo chr(52) . "<br>"; // Decimal value
echo chr(052) . "<br>"; // Octal value
echo chr(0x52) . "<br>"; // Hex value

OUTPUT:
4
*
R

Question 6

Splits a string into a series of smaller parts

Answer 6

chunk_split(string,length,end)
---------------
EXAMPLE:
$str = "Hello world!";
echo chunk_split($str,1,".");

OUTPUT:
H.e.l.l.o. .w.o.r.l.d.!.

Question 7

Decodes a uuencoded string

Answer 7

convert_uudecode(string)
---------------
EXAMPLE:
$str = ",2&5L;&\@=V]R;&0A `";
echo convert_uudecode($str);

OUTPUT:
Hello world!

Question 8

Encodes a string using the uuencode algorithm

Answer 8

convert_uuencode(string)
---------------
EXAMPLE:
$str = "Hello world!";
echo convert_uuencode($str);

OUTPUT:
,2&5L;&\@=V]R;&0A `

Question 9

Returns information about characters used in a string

Answer 9

count_chars(string,mode)
---------------
EXAMPLE:
$str = "Hello World!";
echo count_chars($str,3);

OUTPUT:
The parameter “mode 3” will return a string with all the different characters used. In this example, the characters used in “Hello World!” are:

!HWdelor

Question 10

Outputs one or more strings

Answer 10

EXAMPLE:
echo “Hello world!”;

OUTPUT:
Hello world!

Question 11

Breaks a string into an array

Answer 11

EXAMPLE:
$str = ‘one,two,three,four’;

// zero limit
print_r(explode(',',$str,0));
print "<br>";

// positive limit
print_r(explode(',',$str,2));
print "<br>";

// negative limit 
print_r(explode(',',$str,-1));

OUTPUT:
Array ( [0] => one,two,three,four )
Array ( [0] => one [1] => two,three,four )
Array ( [0] => one [1] => two [2] => three )

Question 12

Writes a formatted string to a specified output stream

Answer 12

fprintf(stream,format,arg1,arg2,arg++)
---------------
EXAMPLE:
$number = 9;
$str = "Beijing";
$file = fopen("test.txt","w");
echo fprintf($file,"There are %u million bicycles in %s.",$number,$str);

OUTPUT:
40

The following text will be written to the file “test.txt”:
There are 9 million bicycles in Beijing.

Question 13

Converts a string of hexadecimal values to ASCII characters

Answer 13

EXAMPLE:
echo hex2bin(“48656c6c6f20576f726c6421”);

OUTPUT:
Hello World!

Question 14

Converts HTML entities to characters

Answer 14

html_entity_decode(string,flags,character-set)
---------------
EXAMPLE:
Jane &amp; 'Tarzan'<br>
Jane &amp; 'Tarzan'<br>
Jane &amp; 'Tarzan'

OUTPUT:
Jane & ‘Tarzan’
Jane & ‘Tarzan’
Jane & ‘Tarzan’

Question 15

Converts characters to HTML entities

Answer 15

EXAMPLE:
$str = “Jane & ‘Tarzan’”;
echo htmlentities($str, ENT_COMPAT); // Will only convert double quotes
echo “<br></br>”;
echo htmlentities($str, ENT_QUOTES); // Converts double and single quotes
echo “<br></br>”;
echo htmlentities($str, ENT_NOQUOTES); // Does not convert any quotes

OUTPUT:
Jane & ‘Tarzan’
Jane & ‘Tarzan’
Jane & ‘Tarzan’

Question 16

Converts some predefined HTML entities to characters

Answer 16

htmlspecialchars_decode(string,flags)
---------------
EXAMPLE:
$str = "This is some <b>bold</b> text.";
echo htmlspecialchars_decode($str);

OUTPUT:
This is some bold text.

Question 17

Converts some predefined characters to HTML entities

Answer 17

htmlspecialchars(string,flags,character-set,double_encode)

The predefined characters are:

& (ampersand) becomes &
" (double quote) becomes "
' (single quote) becomes '
 (greater than) becomes >
---------------
EXAMPLE:
$str = "This is some <b>bold</b> text.";
echo htmlspecialchars($str);

OUTPUT:
This is some <b>bold</b> text.

Question 18

Returns a string from the elements of an array

Answer 18

implode(separator,array)
---------------
EXAMPLE:
$arr = array('Hello','World!','Beautiful','Day!');
echo implode(" ",$arr);

OUTPUT:
Hello World! Beautiful Day!

Question 19

Alias of implode()

Answer 19

join(separator,array)
---------------
EXAMPLE:
$arr = array('Hello','World!','Beautiful','Day!');
echo join(" ",$arr);

OUTPUT:
Hello World! Beautiful Day!

Question 20

Converts the first character of a string to lowercase

Answer 20

EXAMPLE:
echo lcfirst(“Hello world!”);

OUTPUT:
hello world!

Question 21

Returns locale numeric and monetary formatting information

Answer 21

localeconv()
--------------
EXAMPLE:
setlocale(LC_ALL,"US");
$locale_info = localeconv();
print_r($locale_info);

OUTPUT:
Array ( [decimal_point] => . [thousands_sep] => , [int_curr_symbol] => USD [currency_symbol] => $ [mon_decimal_point] => . [mon_thousands_sep] => , [positive_sign] => [negative_sign] => - [int_frac_digits] => 2 [frac_digits] => 2 [p_cs_precedes] => 1 [p_sep_by_space] => 0 [n_cs_precedes] => 1 [n_sep_by_space] => 0 [p_sign_posn] => 3 [n_sign_posn] => 0 [grouping] => Array ( [0] => 3 ) [mon_grouping] => Array ( [0] => 3 ) )

Question 22

Removes whitespace or other characters from the left side of a string

Answer 22

ltrim(string,charlist)
--------------
EXAMPLE:
$str = "Hello World!";
echo $str . "<br>";
echo ltrim($str,"Hello");

OUTPUT:
Hello World!
World!

Question 23

Returns a string formatted as a currency string

Answer 23

money_format(string,number)
--------------
EXAMPLE:
$number = 1234.56;
setlocale(LC_MONETARY,"en_US");
echo money_format("The price is %i", $number);

OUTPUT:
The price is USD 1,234.56

Question 24

Inserts HTML line breaks in front of each newline in a string

Answer 24

EXAMPLE:
echo nl2br(“One line.\nAnother line.”);

OUTPUT:
One line.
Another line.

Question 25

Formats a number with grouped thousands

Answer 25

number_format(number,decimals,decimalpoint,separator)
---------------
EXAMPLE:
echo number_format("1000000")."<br>";
echo number_format("1000000",2)."<br>";
echo number_format("1000000",2,",",".");

OUTPUT:
1,000,000
1,000,000.00
1.000.000,00