Creating character codes from text file

Suppose that I have a text file contains several lines such as the following

My name is John, I studied Chemistry at Okawata University. I am a Canadian citizen but I lived in 123

I want to do the following:

1. I want to remove all punctuation marks fro the text.
2. I want to convert the remaining character including the spaces and the numbers into predefined codes such as: (A: c01, B: c02, ... , a:c27. b:c28) ans also the numbers such as (0:c60, 1:c60, 2:c61) and store the results into another output text file which contains only the codes and each character in a line as follows (suppose the code of the characters of the string "My name": M:c07, y:c30, space:c22, n:c35, ...) so the output file should contain:

c07
c30
c22
c35
..

Answer 1

[Thorsten]

Set up code table X

chars = ['A':'Z' 'a':'z'];
for i = 1:numel(chars)
 X{chars(i)} = sprintf('c%02d', i);
end
digits = '0':'9'
for i = 1:numel(digits)
 X{digits(i)} = sprintf('c%02d', 59+i);
end
X{' '} = 'c22';

Encode string

s = 'My name is John, I studied Chemistry at Okawata University.';
sc = strvcat(X{'My name is John.'})

Note that you don't have to remove the punctuation marks, they are mapped to empty and removed my strvcat.

[dpb]

Good catch on mapping punct to empty... +42 :)

[Mohammad]

Thanks, but how can apply this dolution to Arabic character?

[dpb]

Every character set has its translation...

Answer 2

[dpb]

1. is pretty straightforward to replace characters with empty, thereby removing them entirely. regexp is one way
2. build a "lookup table" of the code desired for each character stored in its ASCII collating sequence. IOW, using your example above for a small subset, since

>> s='My name';
>> double(s)
ans =
  77   121    32   110    97   109   101
>>

store the codes for each of those in those array elements.

Then, since Matlab will do an automagic conversion from character to numeric, you can do the conversion on any converted string simply by

 codedstr=codearray(cleanedInputString).';

and you're done...

I'll leave the intimate details as "exercise for student"... :)