從python中刪除無效符號

我試圖從文本中刪除無效符號。我有這樣的代碼：從python中刪除無效符號

def parse_documentation(filename): 
    filename=open(filename) 
    invalidsymbols=["`","~","!", "@","#","$"] 
    for lines in filename: 
     print(lines) 
     for word in lines: 
     print(word) 
      for letter in word: 
       if invalidsymbols==letter: 
        print(letter)

首先，我只是通過打印測試信件，然後我會添加代碼，刪除（DEL（）），我比在列表中看到的更多的無效符號。但它很多，所以我想用5或6來檢查。我遇到的問題是，它不僅打印無效的符號，而且打印出我的文本中的所有字母。另外，由於某種原因，它還在我的文本之前打印了額外的字符。我如何解決這個問題？

我使用的文字是：

he's a jolly good fellow# 
I want pizza! 
I'm driving to school$

來源

2013-11-20 user2976821

這不是''for'如何與字符串一起工作。 –

@ IgnacioVazquez-Abrams我應該如何訪問每行中的字母？ – user2976821

也許你應該仔細檢查'for'正在做什麼。 –

def parse_documentation(filename): 
    filename=open(filename, "r") # open file 
    lines = filename.read(); # read all the lines in the file to a list named as "lines" 
    invalidsymbols=["`","~","!", "@","#","$"] 
    for line in lines: # for each line in lines 
     for x in invalidsymbols: # loop through the list of invalid symbols 
      if x in line: # if the invalid symbols is in the line 
       print(line) # print out the line 
       print(x) # and also print out the invalid symbol you encountered in that line 
       print(line.replace(x, "")) # print out a line with invalid symbol removed

怎麼樣？

來源

2013-11-20 20:10:38 JoeC

哈哈！感謝那 – JoeC

這個伎倆。謝謝！ – user2976821

歡迎:)每當遇到無效符號時（如果符號出現多次），您仍在打印該行 –

JoeC已經回答了，但我想補充一點，如果你無效符號出現不止一次在該行，那麼你可能會更好做以下

def parse_documentation(filename): 
    filelines = open(filename) 
    invalidsymbols=["`","~","!", "@","#","$"] 
    for line in filelines: 
     print(lines) 
     for symbol in invalidsymbols: 
      if symbol in line: 
       print("Above line contains %s symbol"%symbol)

至於更換的符號，請參閱JoeC's answer。

來源

2013-11-20 20:20:45

您可以str.translate一次全部刪除不需要的符號：

>>> txt = """he's a jolly good fellow# 
... I want pizza! 
... I'm driving to school$""" 
>>> print txt.translate(None, "`[email protected]#$") 
he's a jolly good fellow 
I want pizza 
I'm driving to school

使你的代碼可能是這樣的

def parse_documentation(filename, invalid_symbols): 
    symb_to_remove = ''.join(invalid_symbols) 
    with open(filename, 'rb') as in_file: 
     for line in in_file: 
      safe_line = line.translate(None, symb_to_remove) 
      <here comes code to do smthng with safe_line>

，你會調用這個函數與

parse_documentation(filename, ["`","~","!", "@","#","$"])

來源

2013-11-20 20:23:25 alko

從python中刪除無效符號

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