Goto main content

resub

Perform a regular expression substitute.

RESUB

NAME

resub - Performs a regular expression substitute.

SYNOPSIS

resub("string", "pattern", "substitute" [, "options"]);

DESCRIPTION

Resub matches the pattern specified by the second parameter on the string specified by the first parameter and replaces it with the third parameter.

Resub is based on the library pcrs.

The substitute uses Perl syntax as documented in the perlre(1) manual page, with some exceptions:

Most notably and evidently, since PCRS is not Perl, variable interpolation or Perl command substitution won’t work. Special variables that do get interpolated, are:

$1, $2, …, $n Like in Perl, these variables refer to what the nth capturing subpattern in the pattern matched.

$& and $0 refer to the whole match. Note that $0 is deprecated in recent Perl versions and now refers to the program name.

$+ refers to what the last capturing subpattern matched.

$‘ and $’ (backtick and tick) refer to the areas of the subject before and after the match, respectively. Note that, like in Perl, the unmodified subject is used, even if a global substitution previously matched.

Perl4-style references to subpattern matches of the form \1, \2, … which only exist in Perl5 for backwards compatibility, are not supported.

Also, since the substitute is a double-quoted string in Perl, you might expect all Perl syntax for special characters to apply. In fact, only the following are supported:

\n     newline (0x0a)
\r     carriage return (0x0d)
\t     horizontal tab (0x09)
\f     form feed (0x0c)
\b     backspace (0x08)
\a     alarm, bell (0x07)
\e     escape (0x1b)
\0     binary zero (0x00)

Options The options gmisx are supported. e is not, since it would require a Perl interpreter and neither is o, because the pattern is explicitly compiled, anyway. Additionally, PCRS honors the options U and T. Where PCRE options are mentioned below, refer to PCRE(3) for the subtle differences to Perl behaviour.

g      Replace all instances of pattern in subject, not just the first one.
i      Match the pattern without respect to case. This translates to PCRE_CASELESS.
m      Treat the subject as consisting of multiple lines, i.e.  ’^’ matches immediately after, and ’$’ immediately before each newline.  Translates to PCRE_MULTILINE.
s      Treat the subject as consisting of one single line, i.e.  let the scope of the ’.’ metacharacter include newlines.  Translates to PCRE_DOTALL.
x      Allow extended regular expression syntax in the pattern, enabling whitespace and comments in complex patterns.  Translates to PCRE_EXTENDED.
U      Switch the default behaviour of the ’*’ and ’+’ quantifiers to ungreedy. Note that appending a ’?’ switches back to greedy(!).  The explicit in-pattern switches      (?U)  and  (?-U)  remain  unaf-
       fected.  Translates to PCRE_UNGREEDY.
T      Consider  the  substitute trivial, i.e. do not interpret any references or special character escape sequences in the substitute. Handy for large user-supplied        substitutes, which would otherwise have to be examined and properly quoted.
Unsupported options are silently ignored.

NOTE

Resub does not work well with utf-8 characters. If you want to replace characters to get a valid valid name, use the function esc with the filter filenameutf8.

EXAMPLES

Note: In the followings examples, the _ between the { should be removed to make it work.

res={_{
            a = "Pierre Laplante";
            a.resub("i","x");
            a;
        }}. return res=Pxerre LaplantePierre Laplante.
res={_{
            a = "Pierre Laplante";
            a.resub("e","x");
        }}. return res=Pixrre Laplante.
res={_{
            a = "Pierre Laplante";
            a.resub("e","x","g");
        }}. return res=Pixrrx Laplantx.
res={_{
            a = "Pierre Laplante";
            a.resub("p","x","gi");
        }}. return res=xierre Laxlante.
res={_{
            a = "Pierre Laplante";
            a.resub("([^ ]+) (.*)","$2 $1");
        }}. return res=Laplante Pierre.

SEE ALSO

{{ include("includes/strings.sn") }}

AUTHOR

Written by Pierre Laplante and Caroline Laplante, <laplante@sednove.com>

MODIFICATIONS

1.0 2014-09-09 21:24:14 laplante@sednove.com

Edit

Other topics in sncode,String

addslashes

Quote string with slashes.
base64_decode

Decodes data with MIME base64
base64_encode

Encodes data with MIME base64
bin2hex

Converts binary data into hexadecimal representation
cgidata

parse cgidata
chr

Return a specific character
chunk_split

Split a string into smaller chunks.
Count_chars

Return information about characters used in a string.
crc32

Calculates the crc32 polynomial of a string.
dq

This function is used to use any characters as quotes in string
esc

This function is used to apply a filter to a string.
explode

Split a string by string
extention

Return the length of an expression.
find_in_set

This function is used to check is a value is set within a list with a delimiter between each element.
getnbre

This function returns the number of match regular expression
getoffset

This function returns the position of the last match regular expression
getre

This function return the value of a named parameter in a regular expression.
hex2bin

Decodes a hexadecimally encoded binary string.
hmac

Compute HMAC
html2text

Convert html text to plain text.
htmlentities

Convert all applicable characters to HTML entities.
htmlspecialchars

Convert special characters to HTML entities.
htmlspecialchars_decode

Convert HTML entities to special characters
html_entity_decode

Convert all HTML entities to special characters
implode

Join array elements with a string.
isalnum

This function is used to verify that the argument string contain only alphabetic and digit character.
isalpha

Checks for an alphabetic character.
isascii

Checks whether c is a 7-bit unsigned char value that fits into the ASCII character set.
isblank

Test for whitespace wide character.
iscntrl

Checks for an control character.
isdigit

Checks for a digit (0 through 9).
isfloat

Checks if the argument is a float number.
isgraph

Checks whether c is a character with graphical representation.
isinteger

Checks for a digit (0 through 9) that may be preceed by + or -.
islower

Checks for a lower-case character.
isprint

Checks for any printable character including space.
ispunct

Checks for any printable character which is not a space or an alphanumeric character.
isset

This function is used to check if a value is contained in a list with a delimiter between each element.
isspace

Checks whether c is a white-space character.
isupper

Checks for a upper-case character.
iswalnum

This function is used to verify that the argument string contain only alphabetic and digit character.
iswalpha

Checks for an alphabetic character.
iswblank

Test for whitespace wide character.
iswcntrl

Checks for an control character.
iswdigit

Checks for a digit (0 through 9).
iswgraph

Checks whether c is a character with graphical representation.
iswlower

Checks for a lower-case character.
iswprint

Checks whether c is a character with graphical representation.
iswpunct

Checks for any printable character which is not a space or an alphanumeric character.
iswspace

Checks whether c is a white-space character.
iswupper

Checks for a upper-case character.
iswxdigit

Checks for a hexadecimal digits, i.e. one of 0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F.
isxdigit

Checks for a hexadecimal digits, i.e. one of 0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F.
lc

This function returns the lowercase value of a string.
lcfirst

Returns lc value of the string's first character.
length

Returns the length of an expression
levenshtein

Return the distance between 2 strings.
ltrim

Eliminates whitespace from the beginning of a string.
money_format

Formats a number as a currency string.
nl2br

Inserts HTML line breaks before all newlines in a string
number_format

Formats a number as a regional number string
ord

Return Unicode value of character.
parse

Parse strings.
parse_query_string

This function is used to parse a query string.
print

Output a string.
printf

Print formatted text.
quotemeta

Quote meta characters.
rindex

Locate character in string (last occurence).
rtrim

Strip whitespace (or other characters) from the end of a string.
savecsv

Stores array to a file.
savexls

Export data to xls (Excel format)
setlocale

Strip whitespace (or other characters) from the end of a string.
split

This function is used to split a string.
splitre

This function is used to split a string with a regular expression.
strcasecmp

Case-insensitive string comparison.
strcspn

Find length of initial segment not matching mask.
strinatcmp

Case insensitive string comparisons using a natural order algorithm.
string

Functions for string manipulation
stringnify

Take an expression and return a string.
stripos

Find the position of the first occurrence of a case-insensitive substring in a string.
stripslashes

Un-quotes a quoted string
strip_tags

Strip HTML and extenso tags from a string.
strnatcmp

String comparisons using a natural order algorithm.
strncasecmp

Case-insensitive string comparison of the first n characters.
strncmp

Comparison of the first n characters.
strpos

Find the position of the first occurrence of a substring in a string.
strrev

Reverse a string
strripos

Find the position of the last occurrence of a case-insensitive substring in a string.
strrpos

Find the position of the last occurrence of a substring in a string.
strsub

return a substring from the original string.
strtr

Translate characters or replace substrings.
strtr_ctx

Translate substrings.
strtr_list

Translate substrings.
str_getcsv

Parse a CSV string into an array.
str_ireplace

Replace all occurrences of the search string with the replacement string (case insensitive).
str_pad

Pad a string to a certain length with another string.
str_repeat

Repeat a string
str_replace

Replace all occurrences of the search string with the replacement string.
str_shuffle

Randomly shuffles a string
str_split

Convert a string to an array.
substr

Return part of a string.
trim

Strip whitespace (or other characters) from the end of a string.
trim2

Strip whitespace (or other characters) from the beginning and end of a string.
type

This function return the type of a variable.
uc

This function return the uppercase value of a string.
ucfirst

Make a string's first character uppercase.
ucwords

Uppercase the first character of each word in a string.
unstringnify

Take a string and return an expression.
uriparse

Parse an uri and return its components.
urldecode

Decode a string.
urlencode

Encode a string.
uuid

Create a new unique UUID value
uuid_time

Return the time when a uuid was created.
wordwrap

Wraps a string to a given number of characters.
wstrsub

Returns a substring from the original string.

© 2024 extenso Inc. All rights reserved.