Pyparsing - name not starting with a character - pyparsing

I am trying to use Pyparsing to identify a keyword which is not beginning with $ So for the following input:
$abc = 5 # is not a valid one
abc123 = 10 # is valid one
abc$ = 23 # is a valid one
I tried the following
var = Word(printables, excludeChars='$')
var.parseString('$abc')
But this doesn't allow any $ in var. How can I specify all printable characters other than $ in the first character position? Any help will be appreciated.
Thanks
Abhijit

You can use the method I used to define "all characters except X" before I added the excludeChars parameter to the Word class:
NOT_DOLLAR_SIGN = ''.join(c for c in printables if c != '$')
keyword_not_starting_with_dollar = Word(NOT_DOLLAR_SIGN, printables)
This should be a bit more efficient than building up with a Combine and a NotAny. But this will match almost anything, integers, words, valid identifiers, invalid identifiers, so I'm skeptical of the value of this kind of expression in your parser.

Related

Platform Data Extension: how do I parse ROAD_NAME_FCN

I'm using HERE's Platform Data Extension to retrieve road names. However, I don't understand the strings that I'm getting. I suspect they're encoded somehow but I don't know how to decode them.
For example:
ENGBNFDR Dr NNASN"e|fe "de "e|rre "dri|ve "nol|te;NASY"e|fe "de "e|rre;<snip>
If I split them by a "record separator" character, e.g. link_names.split('\x1e') the values look slightly more intelligible, but only slightly. There are still bizarre abbreviations I don't understand, e.g. ENGBN.
The PDE Layers documents can be found here: http://pde.cit.api.here.com/1/doc/content.html?detail=1&app_id=xxx&app_code=yyy
Layers > ROAD_NAME_FC1 > NAMES.
List of all names for this object, in all languages, latin1/pinyin/phonetic transliterations.
For convenience, non-exonym base names are listed first.
Format:
NAMES = NAME1 \u001D NAME2 \u001D NAME3 ...
NAME = NAME_TEXT \u001E TRANSLIT1 ; TRANSLIT2 ; ... \u001E PHONEME1 ; PHONEME2 ; ... NAME_TEXT = LANGUAGE_CODE NAME_TYPE IS_EXONYM text
TRANSLIT = LANGUAGE_CODE text
PHONEME = LANGUAGE_CODE IS_PREFERRED text
LANGUAGE_CODE is a 3 character string
NAME_TYPE is one letter (A = abbreviation, B = base name, E = exonym, K = shortened name, S = synonym)
IS_EXONYM = Y if the name is a translation into another language
IS_PREFERRED = Y if this is the preferred phoneme.
Please note, the delimiters are:
\u001D between languages (NAMES level)
\u001E between name text, transliterations, and phonemes ';' between different transliterations and phonemes of the same name.

R regex match things other than known characters

For a text field, I would like to expose those that contain invalid characters. The list of invalid characters is unknown; I only know the list of accepted ones.
For example for French language, the accepted list is
A-z, 1-9, [punc::], space, àéèçè, hyphen, etc.
The list of invalid charactersis unknown, yet I want anything unusual to resurface, for example, I would want
This is an 2-piece à-la-carte dessert to pass when
'Ã this Øs an apple' pumps up as an anomalie
The 'not contain' notion in R does not behave as I would like, for example
grep("[^(abc)]",c("abcdef", "defabc", "apple") )
(those that does not contain 'abc') match all three while
grep("(abc)",c("abcdef", "defabc", "apple") )
behaves correctly and match only the first two. Am I missing something
How can we do that in R ? Also, how can we put hypen together in the list of accepted characters ?
[a-z1-9[:punct:] àâæçéèêëîïôœùûüÿ-]+
The above regex matches any of the following (one or more times). Note that the parameter ignore.case=T used in the code below allows the following to also match uppercase variants of the letters.
a-z Any lowercase ASCII letter
1-9 Any digit in the range from 1 to 9 (excludes 0)
[:punct:] Any punctuation character
The space character
àâæçéèêëîïôœùûüÿ Any valid French character with a diacritic mark
- The hyphen character
See code in use here
x <- c("This is an 2-piece à-la-carte dessert", "Ã this Øs an apple")
gsub("[a-z1-9[:punct:] àâæçéèêëîïôœùûüÿ-]+", "", x, ignore.case=T)
The code above replaces all valid characters with nothing. The result is all invalid characters that exist in the string. The following is the output:
[1] "" "ÃØ"
If by "expose the invalid characters" you mean delete the "accepted" ones, then a regex character class should be helpful. From the ?regex help page we can see that a hyphen is already part of the punctuation character vector;
[:punct:]
Punctuation characters:
! " # $ % & ' ( ) * + , - . / : ; < = > ? # [ \ ] ^ _ ` { | } ~
So the code could be:
x <- 'Ã this Øs an apple'
gsub("[A-z1-9[:punct:] àéèçè]+", "", x)
#[1] "ÃØ"
Note that regex has a predefined, locale-specific "[:alpha:]" named character class that would probably be both safer and more compact than the expression "[A-zàéèçè]" especially since the post from ctwheels suggests that you missed a few. The ?regex page indicates that "[0-9A-Za-z]" might be both locale- and encoding-specific.
If by "expose" you instead meant "identify the postion within the string" then you could use the negation operator "^" within the character class formalism and apply gregexpr:
gregexpr("[^A-z1-9[:punct:] àéèçè]+", x)
[[1]]
[1] 1 8
attr(,"match.length")
[1] 1 1

Regular Expression To exclude sub-string name(job corps) Includes at least 1 upper case letter, 1 lower case letter, 1 number and 1 symbol except "#"

Regular Expression To exclude sub-string name(job corps)
Includes at least 1 upper case letter, 1 lower case letter, 1 number and 1 symbol except "#"
I have written something like below :
^((?!job corps).)(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[!#$%^&*]).*$
I tested with the above regular expression, not working for special character.
can anyone guide on this..
If I understand well your requirements, you can use this pattern:
^(?![^a-z]*$|[^A-Z]*$|[^0-9]*$|[^!#$%^&*]*$|.*?job corps)[^#]*$
If you only want to allow characters from [a-zA-Z0-9^#$%&*] changes the pattern to:
^(?![^a-z]*$|[^A-Z]*$|[^0-9]*$|[^!#$%^&*]*$|.*?job corps)[a-zA-Z0-9^#$%&*]*$
details:
^ # start of the string
(?! # not followed by any of these cases
[^a-z]*$ # non lowercase letters until the end
|
[^A-Z]*$ # non uppercase letters until the end
|
[^0-9]*$
|
[^!#$%^&*]*$
|
.*?job corps # any characters and "job corps"
)
[^#]* # characters that are not a #
$ # end of the string
demo
Note: you can write the range #$%& like #-& to win a character.
stribizhev, your answer is correct
^(?!.job corps)(?=.[0-9])(?=.[a-z])(?=.[A-Z])(?=.[!#$%^&])(?!.#).$
can verify the expression in following url:
http://www.freeformatter.com/regex-tester.html

String recognition in idl

I have the following strings:
F:\Sheyenne\ROI\SWIR32_subset\SWIR32_2005210_East_A.dat
F:\Sheyenne\ROI\SWIR32_subset\SWIR32_2005210_Froemke-Hoy.dat
and from each I want to extract the three variables, 1. SWIR32 2. the date and 3. the text following the date. I want to automate this process for about 200 files, so individually selecting the locations won't exactly work for me.
so I want:
variable1=SWIR32
variable2=2005210
variable3=East_A
variable4=SWIR32
variable5=2005210
variable6=Froemke-Hoy
I am going to be using these to add titles to graphs later on, but since the position of the text in each string varies I am unsure how to do this using strmid
I think you want to use a combination of STRPOS and STRSPLIT. Something like the following:
s = ['F:\Sheyenne\ROI\SWIR32_subset\SWIR32_2005210_East_A.dat', $
'F:\Sheyenne\ROI\SWIR32_subset\SWIR32_2005210_Froemke-Hoy.dat']
name = STRARR(s.length)
date = name
txt = name
foreach sub, s, i do begin
sub = STRMID(sub, 1+STRPOS(sub, '\', /REVERSE_SEARCH))
parts = STRSPLIT(sub, '_', /EXTRACT)
name[i] = parts[0]
date[i] = parts[1]
txt[i] = STRJOIN(parts[2:*], '_')
endforeach
You could also do this with a regular expression (using just STRSPLIT) but regular expressions tend to be complicated and error prone.
Hope this helps!

grep on two strings

I'm working to grab two different elements in a string.
The string look like this,
str <- c('a_abc', 'b_abc', 'abc', 'z_zxy', 'x_zxy', 'zxy')
I have tried with the different options in ?grep, but I can't get it right, 'm doing something like this,
grep('[_abc]:[_zxy]',str, value = TRUE)
and what I would like is,
[1] "a_abc" "b_abc" "z_zxy" "x_zxy"
any help would be appreciated.
Use normal parentheses (, not the square brackets [
grep('_(abc|zxy)',str, value = TRUE)
[1] "a_abc" "b_abc" "z_zxy" "x_zxy"
To make the grep a bit more flexible, you could do something like:
grep('_.{3}$',str, value = TRUE)
Which will match an underscore _ followed by any character . three times {3} followed immediately by the end of the string $
this should work: grep('_abc|_zxy', str, value=T)
X|Y matches when either X matches or Y matches
In this case just doing:
str[grep("_",str)]
will work... is it more complicated in your specific case?

Resources