strings/

mg_streplace.pro

includes main-level program

Routines

top mg_streplace

result = mg_streplace(str, pattern, replacement [, /evaluate] [, /fold_case] [, /global])

Handle string replacment with regular expressions.

Return value

string

Parameters

str in required type=string

a string to search for expressions and replace them

pattern in required type=string

a regular expression possibly using subexpressions; see IDL's online help for STREGEX for help on regular expressions

replacement in required type=string

the string to replace matches of the "pattern"; can use $1, $2, etc. to refer to subexpressions in "pattern"

Keywords

evaluate in optional type=boolean

set to evaluate the "replacement" as a IDL expression instead of just a string.

fold_case in optional type=boolean

set to make a case insensitive match with "pattern"

global in optional type=boolean

set to replace all expressions that match

start out optional private type=integral default=0

index into string of where to start looking for the pattern

Examples

The following example demonstrates basic operations of MG_STREPLACE, simply replacing "was" with "was not" in the expression "Mike was here":

  IDL> print, mg_streplace('Mike was here', 'was', 'was not')
  Mike was not here

Meta-variables $1, $2, etc. represent matched values in parentheses. This swaps the first two words in the string:

  IDL> print, mg_streplace('Mike was here', '([^ ]*) ([^ ]*)', '$2 $1')
  was Mike here

Capitalize the name following "Mike". Here, EVALUATE and GLOBAL replace all patching expressions with an evaluated expression:

  IDL> s = 'MikeGeorgeHenryMikeBill'
  IDL> re = 'Mike([A-Z][a-z]*)'
  IDL> expr = '"Mike" + strupcase($1)'
  IDL> print, mg_streplace(s, re, expr, /evaluate, /global)
  MikeGEORGEHenryMikeBILL

Another evaluated expression:

  IDL> re = 'Mike([0-9]+)'
  IDL> expr = 'fix($1) * 2'
  IDL> help, mg_streplace('Mike5', re, expr, /evaluate)
  <Expression>    LONG      =           10

Here's an example to put grouping commas into a long integer value:

  IDL> str = '1874382735872851'
  IDL> re = '^[+-]?([[:digit:]]+)([[:digit:]]{3})'
  IDL> for i = 0, strlen(str) / 3 - 1 do $
  IDL>   str = mg_streplace(str, re, '$1,$2', /global)
  IDL> print, str
  1,874,382,735,872,851

Author information

Author:: Michael Galloy

File attributes

Modification date:	Wed May 14 15:07:14 2014
Lines:	76
Docformat:	rst rst

Personal library of Michael Galloy
Contact me if you have enhancement requests or bug fixes.

mglib

Personal IDL library for M. Galloy