python - online - ¿Cómo introducir una expresión regular en string.replace?

regular expression |]

Question

Necesito un poco de ayuda para declarar una expresión regular. Mis entradas son como las siguientes:

this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>. 
and there are many other lines in the txt files
with<[3> such tags </[3>

La salida requerida es:

this is a paragraph with in between and then there are cases ... where the number ranges from 1-100. 
and there are many other lines in the txt files
with such tags

He intentado esto:

#!/usr/bin/python
import os, sys, re, glob
for infile in glob.glob(os.path.join(os.getcwd(), ''*.txt'')):
    for line in reader: 
        line2 = line.replace(''<[1> '', '''')
        line = line2.replace(''</[1> '', '''')
        line2 = line.replace(''<[1>'', '''')
        line = line2.replace(''</[1>'', '''')

        print line

También he intentado esto (pero parece que estoy usando la sintaxis de expresiones regulares incorrecta):

    line2 = line.replace(''<[*> '', '''')
    line = line2.replace(''</[*> '', '''')
    line2 = line.replace(''<[*>'', '''')
    line = line2.replace(''</[*>'', '''')

No quiero codificar la replace de 1 a 99. . .

Answer 1

El método de reemplazar objetos de cadena no acepta expresiones regulares, sino solo cadenas fijas (consulte la documentación: http://docs.python.org/2/library/stdtypes.html#str.replace ).

Tienes que usar re modulo:

import re
newline= re.sub("<//?/[[0-9]+>", "", line)

Answer 2

Este fragmento de código probado debe hacerlo:

import re
line = re.sub(r"</?/[/d+>", "", line)

Edición: Aquí hay una versión comentada que explica cómo funciona:

line = re.sub(r"""
  (?x) # Use free-spacing mode.
  <    # Match a literal ''<''
  /?   # Optionally match a ''/''
  /[   # Match a literal ''[''
  /d+  # Match one or more digits
  >    # Match a literal ''>''
  """, "", line)

¡Los regexes son divertidos! Pero recomendaría encarecidamente pasar una o dos horas estudiando lo básico. Para empezar, necesita aprender qué caracteres son especiales: "metacaracteres" que deben escaparse (es decir, con una barra invertida colocada al frente y las reglas son diferentes dentro y fuera de las clases de caracteres). Hay un excelente tutorial en línea en: www.regular-expressions.info . El tiempo que pases allí se pagará por sí mismo muchas veces. Feliz regexing!

Answer 3

La forma más fácil

import re

txt=''this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>.  and there are many other lines in the txt files with<[3> such tags </[3>''

out = re.sub("(<[^>]+>)", '''', txt)
print out

Answer 4

Me gustaría esto (expresiones regulares explicadas en los comentarios):

import re

# If you need to use the regex more than once it is suggested to compile it.
pattern = re.compile(r"</{0,}/[/d+>")

# <//{0,}/[/d+>
# 
# Match the character “<” literally «<»
# Match the character “/” literally «//{0,}»
#    Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «{0,}»
# Match the character “[” literally «/[»
# Match a single digit 0..9 «/d+»
#    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
# Match the character “>” literally «>»

subject = """this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>. 
and there are many other lines in the txt files
with<[3> such tags </[3>"""

result = pattern.sub("", subject)

print(result)

Si desea obtener más información sobre expresiones regulares, le recomiendo leer el libro de recetas de Expresiones regulares de Jan Goyvaerts y Steven Levithan.

Answer 5

no tiene que usar expresiones regulares (para su cadena de muestra)

>>> s
''this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>. /nand there are many other lines in the txt files/nwith<[3> such tags </[3>/n''

>>> for w in s.split(">"):
...   if "<" in w:
...      print w.split("<")[0]
...
this is a paragraph with
 in between
 and then there are cases ... where the
 number ranges from 1-100
.
and there are many other lines in the txt files
with
 such tags

Answer 6

str.replace() hace reemplazos fijos. Utilice re.sub() lugar.