# Basic syntax:
import re
len(re.findall('[characters]', your_string))
# Example usage:
# say you want to count all G, g, C, or c characters in the following DNA seq
len(re.findall('[GgCc]', "ACGTGCAcgattcgatCGCTAGCTAG"))
--> 14
#using dict comprehensions
sentence = "This is a long sentence that I have just written up for an example!"
dicto = {char: sentence.count(char) for char in set(sentence)}
print(dicto)#This returns a dictionary with the letter and amount of times it shows up in your sentence
#output: {'f': 1, 'u': 2, 't': 6, 's': 4, 'j': 1, 'o': 2, 'I': 1, 'r': 2, 'p': 2, 'w': 1, '!': 1, 'l': 2, 'n': 5, 'g': 1, 'T': 1, 'a': 5, 'h': 3, 'i': 3, 'v': 1, 'm': 1, 'e': 7, 'c': 1, ' ': 13, 'x': 1}
#sorted low to high:
print({k: v for k, v in sorted(dicto.items(), key=lambda item: item[1])})
#{'g': 1, 'x': 1, 'j': 1, 'f': 1, '!': 1, 'T': 1, 'w': 1, 'v': 1, 'I': 1, 'm': 1, 'c': 1, 'o': 2, 'u': 2, 'r': 2, 'l': 2, 'p': 2, 'i': 3, 'h': 3, 's': 4, 'n': 5, 'a': 5, 't': 6, 'e': 7, ' ': 13}
#Python program count all characters in a text
root = "..Desktop ext.txt"
file = open(root, 'rt', encoding="utf-8")
data = file.read()
counter = data.count('a')+data.count('A')+data.count('b')+data.count('B')+data.count('c')+data.count('C')+data.count('d')+data.count('D')+data.count('e')+data.count('E')+data.count('f')+data.count('F')+data.count('g')+data.count('G')+data.count('h')+data.count('H')+data.count('i')+data.count('I')+data.count('g')+data.count('G')+data.count('k')+data.count('K')+data.count('l')+data.count('L')+data.count('m')+data.count('M')+data.count('n')+data.count('N')+data.count('o')+data.count('O')+data.count('p')+data.count('P')+data.count('q')+data.count('q')+data.count('r')+data.count('R')+data.count('s')+data.count('S')+data.count('t')+data.count('T')+data.count('u')+data.count('U')+data.count('v')+data.count('V')+data.count('w')+data.count('W')+data.count('x')+data.count('X')+data.count('y')+data.count('Y')+data.count('z')+data.count('Z')
print(counter)
#684004