如何替换所有出现的某些字符？

I am reading a csv into a:

我正在读一个csv到：

import csv
import collections
import pdb
import math
import urllib

def do_work():
  a=get_file('c:/pythonwork/cds/cds.csv')
  a=remove_chars(a)
  print a[0:10]

def get_file(start_file): #opens original file, reads it to array
  with open(start_file,'rb') as f:
    data=list(csv.reader(f))
  return (data)

def remove_chars(a):
  badchars=['a','b','c','d']
  for row in a:
    for letter in badchars:
      row[8].replace(letter,'')
  return a

I would like to replace all occurrences of ['a','b','c','d'] in the 8th element of the line with empty string. the remove_chars function is not working.

我想用空字符串替换行的第8个元素中出现的所有['a'，'b'，'c'，'d']。 remove_chars函数不起作用。

Is there a better way to do this?

有一个更好的方法吗？

3 个解决方案

#1

The problem is you're not doing anything with the result of replace. In Python strings are immutable so anything that manipulates a string returns a new string instead of modifying the original string.

问题是你没有对替换的结果做任何事情。在Python中，字符串是不可变的，因此操作字符串的任何内容都会返回一个新字符串，而不是修改原始字符串。

line[8] = line[8].replace(letter, "")

#2

I would use the translate method without translation table. It deletes the letters in second argument in recent Python versions.

我会使用没有转换表的translate方法。它删除了最近Python版本中第二个参数中的字母。

def remove_chars(line):
    line7=line[7].translate(None,'abcd')
    return line[:7]+[line7]+line[8:]

line= ['ad','da','sdf','asd',
        '3424','342sfas','asdfaf','sdfa',
        'afase']
print line[7]
line = remove_chars(line)
print line[7]

#3

You really should have multiple input, e.g. one for firstname, middle names, lastname and another one for age. If you want to have some fun though you could try:

你真的应该有多个输入，例如一个用于名字，中间名，姓氏，另一个用于年龄。如果你想要玩得开心，你可以尝试：

>>> input_given="join smith 25"
>>> chars="".join([i for i in input_given if not i.isdigit()])
>>> age=input_given.translate(None,chars)
>>> age
'25'
>>> name=input_given.replace(age,"").strip()
>>> name
'join smith'

This would of course fail if there is multiple numbers in the input. a quick check would be:

如果输入中有多个数字，这当然会失败。快速检查将是：

assert(age in input_given)

and also:

并且：

assert(len(name)<len(input_given))

#1