HOW THE QUIZ WORKS:
Clicking the ‘randomize’ button situated above the reference table generates a new table whereby the function descriptions, function syntaxes, and function return values are randomized. The quiz involves matching the function descriptions, function syntaxes, and function return values to the correct function name. Information relating to the randomization of table cells will be displayed for three seconds, before disappearing.
On a desktop computer, table elements are selected by left-clicking the desired table cell and holding the left click in the mouse down position for one second before releasing the left click. The text inside the table cell will turn red to indicate that the one-second mouse left-click has successfully selected a table cell. To then swap the selected table cell with the target table cell, simply repeat the one-second left mouse-click process on the target cell; the table cells will swap position. To de-select a table cell, simply repeat the one-second left mouse-click process on the original table cell.
To select a table element on a touchscreen device (mobile, tablet), simply touch the desired table cell and maintain the touch for one second before removing your finger from the screen. The text inside the table cell will turn red to indicate that the one-second touch has successfully selected a table cell. To then swap the selected table cell with the target table cell, simply repeat the one-second touch process on the target cell; the table cells will swap position. To de-select a table cell, simply repeat the one-second touch process on the original table cell.
Normal touchscreen scrolling behaviour is exhibited by the cells with a light green background; cells without a light green background will not respond to normal touchscreen scrolling. The table is positioned in such a way that the user can also initiate touchscreen scrolling by swiping to the right or left of the table.
When a row consists of the correct function name, function description, function syntax, and function return value, the background colour of the row will change from ‘transparent’ to ‘khaki’; this provides visual feedback that the row is complete.
Once the entire table is complete, a paragraph of feedback will congratulate the user and provide the following information: date and time of quiz commencement; date and time of quiz completion; and the length of time it took the user to complete the quiz.
VIEWPORT OPTIONS:
PURPOSE:
This webpage serves two purposes:
- It provides a reference table for the PHP string functions, with information extracted and condensed from w3schools.com and php.net.
- It enables users to complete a quiz related to the PHP string functions.
USAGE:
For each string function there are four table cells of information: the function name; the function description; the function syntax; and the function return value. There are three layouts available – ‘mobile‘, ‘tablet‘, and ‘desktop‘.
Click the relevant button below to display the PHP string functions reference table, sized appropriately for the desired viewport. A ‘RANDOMIZE‘ button appears above the reference table once the viewport is selected; clicking this button facilitates the commencement of a quiz.
Click the ‘RANDOMIZE‘ button to randomize the functional descriptions, the functional syntaxes, and the functional return information.
| FUNCTION NAME | FUNCTION DESCRIPTION | FUNCTION SYNTAX | FUNCTION RETURN VALUE |
|---|---|---|---|
htmlspecialchars()
[Convert special characters to HTML entities] |
This function returns a string with certain characters – that have a special meaning in HTML – converted to entities. The following characters will be translated: ampersand; double quote; single quote; ‘less than’ sign; and the ‘greater than’ sign. | htmlspecialchars(string, flags [optional parameter, default value of ENT_COMPAT|ENT_HTML401], encoding [optional parameter, default value of ini_get(“default_charset”)], double_encode [optional parameter, default value of TRUE]); |
htmlspecialchars(): returns the converted string. An empty string will be returned if string contains an invalid code unit sequence within the given encoding, unless either the ENT_IGNORE or ENT_SUBSTITUTE flags are set. |
implode()
[Join array elements with a string] |
This function condenses [‘implodes’] pieces_array into a string, compressing the array elements with glue_string. glue_string defaults to an empty string. This function is an alias of join(). |
implode(glue_string [optional parameter, with a default value of an empty string], pieces_array); |
implode(): returns a string containing a string representation of the imploded array, with glue_string between each element. |
lcfirst()
[Make a string’s first character lowercase] |
Returns a string with the first character of string lowercased if that character is ‘alphabetic’. ‘Alphabetic’ is determined with reference to the current locale; in the default ‘C’ locale, characters such as umlaut-a will not be converted. | lcfirst(string); |
lcfirst(): returns string with its first character lowercased if the character is deemed ‘alphabetic’; otherwise it returns the input string. |
levenshtein()
[Calculate Levenshtein distance between two strings] |
The Levenshtein distance is defined as the minimum number of characters you have to replace, insert, or delete to transform string_1 into string_2. The simplest form of the function just calculates the number of replace, insert, or delete operations needed to transform string_1 into string_2. A more general and adaptive – but less efficient – variant takes three extra parameters that define the cost of replace, insert, and delete operations. | Variant One:levenshtein(string_1, string_2);Variant Two: levenshtein(string_1, string_2, insert_cost, replace_cost, delete_cost); |
levenshtein(): returns the Levenshtein-Distance between string_1 and string_2 OR -1 if one of the strings is longer than 255 characters. |
localeconv()
[Get numeric formatting information] |
Returns an associative array containing localized numeric and monetary formatting information. Returns data based on the current locale as defined by setlocale(). |
localeconv(); |
localeconv(): returns an associative array containing locale-specific numeric formatting information. Elements comprise: ‘decimal_point’; ‘thousands_sep’; ‘grouping’; ‘int_curr_symbol’; ‘currency_symbol’; ‘mon_decimal_point’; ‘mon_thousands_sep’; ‘mon_grouping’; ‘positive_sign’; ‘negative_sign’; ‘int_frac_digits’; ‘frac_digits’; ‘p_cs_precedes’; ‘p_sep_by_space’; ‘n_cs_precedes’; ‘n_sep_by_space’; ‘p_sign_posn’; and ‘n_sign_posn’. |
ltrim()
[Strip whitespace (or other characters) from the beginning of a string] |
This function strips (‘trims’) whitespace (or other characters) from the beginning (left-hand side) of string. | ltrim(string, character_mask [optional parameter – simply list all the characters you want stripped; using ‘..’ defines a range]); |
ltrim(): returns a string with whitespace (and any other characters specified in character_mask) trimmed from the start of string.If no further characters are specified in the character_mask parameter, ltrim() will strip the following characters: an ordinary space; a tab; a newline; a carriage return; the NUL-byte; and a vertical tab. |
md5_file()
[Calculates the md5 hash of a given file] |
Calculates the MD5 hash of the specified file, using the RSA Data Security, Inc. MD5 Message-Digest Algorithm, and returns that hash [a 32-character hexadecimal number]. | md5_file(file, raw_output [optional parameter, with a default value of FALSE]);
[When raw_output is TRUE, the digest is returned in raw binary format with a length of 16.] |
md5_file(): returns a string on success; FALSE otherwise. |
md5()
[Calculate the md5 hash of a string] |
Calculates the MD5 hash of string, using the RSA Data Security, Inc. MD5 Message-Digest Algorithm, and returns that hash. Owing to the fast nature of the hashing algorithm, it is not recommended to use this function to secure passwords. | md5(string, raw_output[optional parameter, with a default value of FALSE]);
[If raw_output is set to TRUE, the md5 digest is returned in raw binary format with a length of 16.] |
md5(): returns the MD5 hash of string. |
metaphone()
[Calculate the metaphone key of a string] |
Calculates the metaphone key of string. Similar to soundex(), but more accurate since it knows the basic rules of English pronunciation. The metaphone-generated keys are of variable length. |
metaphone(string, phonemes [optional parameter, defaulting to 0 – meaning ‘no restriction’]); |
metaphone(): returns the metaphone key as a string on success; FALSE on failure. |
money_format()
[Formats a number as a currency string] |
This function returns a monetarily–formatted version of number. It wraps the C library function strfmon(), with the difference that this function converts only one number at a time; this function is only defined on systems that implement strfmon capabilities. |
money_format(format, number);
[The format sequence is as follows: a percentage character — optional flags — optional field width — optional left precision — optional right precision — a required conversion character.] |
money_format(): returns the monetarily–formatted string. Characters preceding and succeeding the format string will be returned unchanged. A non-numeric number causes NULL to be returned and an E_WARNING to be emitted. |
nl_langinfo()
[Query language and locale information] |
nl_langinfo() is used to access individual elements of the locale categories; it allows you to select any specific element. |
nl_langinfo(item);
[item may be an integer value of the element or the constant name of the element. The following constant names can be used: ABDAY_(1-7); DAY_(1-7); ABMON_(1-12); MON_(1-12); AM_STR; PM_STR; D_T_FMT; D_FMT; T_FMT; T_FMT_AMPM; ERA; ERA_YEAR; ERA_D_T_FMT; ERA_D_FMT; ERA_T_FMT; INT_CURR_SYMBOL; CURRENCY_SYMBOL; CRNCYSTR; MON_DECIMAL_POINT; MON_THOUSANDS_SEP; MON_GROUPING; POSITIVE_SIGN; NEGATIVE_SIGN; INT_FRAC_DIGITS; FRAC_DIGITS; P_CS_PRECEDES; P_SEP_BY_SPACE; N_CS_PRECEDES; N_SEP_BY_SPACE; P_SIGN_POSN; N_SIGN_POSN; DECIMAL_POINT; RADIXCHAR; THOUSANDS_SEP; THOUSEP; GROUPING; YESEXPR; NOEXPR; YESSTR; NOSTR; or CODESET.] |
nl_langinfo(): returns the element as a string; FALSE on failure. |