PHP String Function Mini-Quiz 9: From `substr_count()` to `wordwrap()`.

Chris Larham [Site Administrator]

8 years ago

The substr_count PHP string function, sized for tablet viewing.

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:

An example of the layout designed for mobile phones

An example of the layout designed for tablets

An example of the layout designed for desktop computers

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
`substr_count()` [Count the number of substring occurrences]	This function returns the number [‘count’] of times the `needle` substring occurs in the `haystack` string. `needle` is case-sensitive.	`substr_count(haystack, needle, offset` [optional parameter with a default value of 0]`, length` [optional parameter]`);` [`offset` specifies the position at which to start counting. If negative, the comparison begins at `offset` characters from the end of the string. `length` specifies the maximum length after `offset` to search for the `needle`. A WARNING is output if `offset` plus `length` is greater than the `haystack` length. A negative `length` counts from the end of `haystack`.]	`substr_count()`: returns an integer representation of the number of occurrences of `needle` within `haystack`.
`substr_replace()` [Replace text within a portion of a string]	This function replaces a copy of `string` delimited by the `start` and optional `length` parameters [thus, a ‘substring’] with the `replacement` string.	`substr_replace(string, replacement, start, length` [optional parameter, with a default value of `strlen(string)`]`);` [`string` represents the input string. An array of strings can be provided; in this case, the replacements will occur on each string in turn. `replacement`, `start`, and `length` may be provided as either scalar values or as arrays (whereby the corresponding array element will be used for each input string). `replacement` defines the replacement string. If `start` is non-negative, the replacing will begin at the start^th offset into `string`. If negative, the replacing will begin at the start^th character from the end of `string`. If `length` is given and non-negative, it represents the length of the portion of `string` which is to be replaced. If negative, `length` represents the number of characters from the end of `string` at which replacing will end. Its default value is `strlen(string)`. If `length` is `0`, `replacement` will be inserted into `string` at the `start` offset.]	`substr_replace()`: the *result string* is returned. If `string` is an array, then an array is returned.
`substr()` [Return part of a string]	This function returns the portion [‘substring’] of `string` specified by the `start` and `length` parameters.	`substr(string, start, length` [optional parameter]`);` [`string` represents the input string; must be one character or longer. If `start` is non-negative, the returned string will begin at the `start`^th position in `string` counting from 0. If `start` is negative, the returned string will begin at the `start`^th character from the end of `string`. If `string` is less than `start` characters long, FALSE will be returned. If `length` is given and is positive, the string returned will contain at most `length` characters beginning from `start`. If `length` is negative, `length` characters will be omitted from the end of `string`. FALSE will be returned if `start` denotes the position of this truncation or beyond. An empty string will be returned if `length` is 0, FALSE, or NULL. If `length` is omitted, the substring starting from `start` till the end of `string` will be returned.]	`substr()`: returns the extracted part of `string` [the ‘substring’]; FALSE on failure, or an empty string.
`trim()` [Strip whitespace (or other characters) from the beginning and end of a string]	This function returns a string with whitespace stripped [‘trimmed’] from the beginning and end of `string`. If `character_mask` is unspecified, `trim()` will strip the following characters: an ordinary space; a tab; a new line; a carriage return; the NUL-byte; and the vertical tab.	`trim(string, character_mask` [optional parameter, with a default value of `“\t\n\r\0\x0B”`]`);` [Further characters can be specified in the `character_mask` parameter. With .., a range of characters can be specified.]	`trim()`: returns the trimmed string.
`ucfirst()` [Make a string’s first character uppercase]	This function returns a string with the first character of `string` capitalized [‘uppercased’], if that character is alphabetic. ‘Alphabetic’ is determined by the current locale; in the default C locale, characters such as umlaut-a will not be capitalized.	`ucfirst(string);`	`ucfirst()`: returns the resulting string, after its first character has been uppercased if it is suitably ‘alphabetic’.
`ucwords()` [Uppercase the first character of each word in a string]	This function returns a string with the first character of each word in `string` capitalized [‘uppercased’], if that character is ‘alphabetic’. A ‘word’ is defined as any string of characters that is immediately after any character listed in the `delimiters` parameter.	`ucwords(string, delimiters` [optional parameter, with a default value of `" \t\r\n\f\v"`]`);` [The optional `delimiters` parameter contains the word separator characters. By default these are: space; horizontal tab; carriage return; form-feed; newline; and vertical tab.]	`ucwords()`: returns the modified string, after the first character of all words have been uppercased if suitably ‘alphabetic’.
`vfprintf()` [Write a formatted string to a stream]	This function writes [‘prints’] a string produced according to `format` to the stream resource specified by `handle`. Operates as `fprintf()` but accepts an array of `args`, rather than a variable number of arguments.	`vfprintf(handle, format, args);` [See `sprintf()` for more details on the `format` directives. Possible type specifiers: `%` (a literal percentage character); `b` (treated as integer, presented as binary); `c` (treated as integer, presented as character with that ASCII value); `d` (treated as integer, presented as signed decimal number); `e` (treated as scientific notation); `E` (uppercase scientific notation); `f` (treated as a float, presented as locale-aware floating-point number); `F` (treated as a float, presented as non-locale-aware floating-point number); `g` (shorter of %e and %f); `G` (shorter of %E and %f); `o` (treated as an integer, presented as an octal number); `s` (treated and presented as a string); `u` (treated as integer, presented as unsigned decimal number); `x` (treated as integer, presented as lowercase hexadecimal number); and `X` (treated as integer, presented as uppercase hexadecimal number).]	`vfprintf()`: returns the length of the outputted string.
`vprintf()` [Output a formatted string]	This function displays [‘prints’] array values as a string formatted according to `format`. Operates as `printf()` but accepts an array of arguments, rather than a variable number of arguments.	`vprintf(format, args);` [See `sprintf()` for more details on the `format` directives. See `vfprintf()` for further information on the possible type specifiers.]	`vprintf()`: returns the length of the outputted string.
`vsprintf()` [Return a formatted string]	`vsprintf()` operates as `sprintf()` but accepts an array of arguments, rather than a variable number of arguments.	`vsprintf(format, args);` [See `sprintf()` for more details on the `format` directives. See `vfprintf()` for further information on the possible type specifiers.]	`vsprintf()`: returns the array values as a string formatted according to `format`.
`wordwrap()` [Wraps a string to a given number of characters]	This function wraps a string [‘word’] to a given number of characters using a string break character.	`wordwrap(string, width` [optional parameter, default value = 75]`, break` [optional parameter, default value = `"\n"`]`, cut` [optional parameter, default value = FALSE]`);` [If `cut` is set to TRUE, the string is always wrapped at or before `width`. When FALSE, the function does not split the word even if it is wider than `width`.]	`wordwrap()`: returns the given string [‘word’] wrapped at the specified length.

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HOW THE QUIZ WORKS:

VIEWPORT OPTIONS:

PURPOSE:

USAGE:

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