CODEWITHSUNDEEP
pythonstringlistreplace
Pv L
Pv L

Reputation: 59

Removing a character from a string in a list of lists

I'm trying to format some data for performing an analysis. I'm trying to remove '*' from all strings that start with one. Here's a snippet of the data: 

[['Version', 'age', 'language', 'Q1', 'Q2', 'Q3', 'Q4', 'Q5', 'Q6', 'Q7', 'Q8', 'Q9', 'Q10', 'Q11', 'Q12', 'Q13', 'Q14', 'Q15', 'Q16', 'Q17', 'Q18', 'Q19', 'Q20', 'Q21', 'Q22', 'Q23', 'Q24', 'Q25', 'Q26', 'Q27', 'Q28', 'Q29', 'Q30', 'Q31', 'Q32', 'Q33', 'Q34', 'Q35', 'Q36', 'Q37', 'Q38', 'Q39', 'Q40', 'Q41', 'Q42', 'Q43', 'Q44', 'Q45'], ['1', '18 to 40', 'English', '*distort', '*transfer', '*retain', 'constrict', '*secure', '*excite', '*cancel', '*hinder', '*overstate', 'channel', '*diminish', '*abolish', '*comprehend', '*tolerate', '*conduct', '*destroy', '*foster', 'direct', '*challenge', 'forego', '*cause', '*reduce', 'interrupt', '*enhance', '*misapply', '*exhaust', '*extinguish', '*assimilate', 'believe', 'harmonize', '*demolish', 'affirm', 'trouble', 'discuss', '*force', 'divide', '*remove', '*release', 'highlight', 'reinforce', 'stifle', '*compromise', '*experience', 'evaluate', 'replenish']]

This should be simple, but nothing I've tried works. For example:

for lst in testList:
    for item in lst:
        item.replace('*', '')

just gives me back the same strings. I've also tried inserting an if statement and indexing the characters in the strings. I know I can access the strings. For example if I say if item[0] == '*': print item it prints the correct items.

Upvotes: 4

Views: 11673

Answers (5)

Janion
Janion

Reputation: 118

In your code you were replacing the * in the dummy variable only and not effecting the list entry. Using lstrip will only take the * from the left had side of the string.

for x in xrange(len(testList)):
    testList[x] = testList[x].lstrip('*')

Upvotes: 0

Michael Neylon
Michael Neylon

Reputation: 624

y = []
for lst in testList:
    for a in lst:
        z = a.replace('*','')
        y.append(z)
testList = []
testList.append(y)
print testList

Upvotes: 0

TigerhawkT3
TigerhawkT3

Reputation: 49318

You'll have to either create a new list (demonstrated below) or access the indices of the old one.

new_list = [[item.replace('*','') if item[0]=='*' else item for item in l] for l in old_list]

Upvotes: 0

JuniorCompressor
JuniorCompressor

Reputation: 20015

You can try using enumerate in order to have access to list element's index when the time comes and you need to change it:

 for lst in testList:
      for i, item in enumerate(lst):
          if item.startswith('*'):
               lst[i] = item[1:] # Or lst[i] = item.replace('*', '') for more

Upvotes: 2

Anand S Kumar
Anand S Kumar

Reputation: 90899

strings are immutable , and as such item.replace('*','') returns back the string with the replaced characters, it does not replace them inplace (it cannot , since strings are immutable) . you can enumerate over your lists, and then assign the returned string back to the list -

Example -

for lst in testList:
    for j, item in enumerate(lst):
        lst[j] = item.replace('*', '')

You can also do this easily with a list comprehension -

testList = [[item.replace('*', '') for item in lst] for lst in testList]

Upvotes: 9

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