How do I compare two strings in python?

问题

I have two strings like

string1="abc def ghi"

and

string2="def ghi abc"

How to get that this two string are same without breaking the words?

回答1:

Seems question is not about strings equality, but of sets equality. You can compare them this way only by splitting strings and converting them to sets:

s1 = 'abc def ghi'
s2 = 'def ghi abc'
set1 = set(s1.split(' '))
set2 = set(s2.split(' '))
print set1 == set2

Result will be

True

回答2:

If you want to know if both the strings are equal, you can simply do

print string1 == string2

But if you want to know if they both have the same set of characters and they occur same number of times, you can use collections.Counter, like this

>>> string1, string2 = "abc def ghi", "def ghi abc"
>>> from collections import Counter
>>> Counter(string1) == Counter(string2)
True

回答3:

>>> s1="abc def ghi"
>>> s2="def ghi abc"
>>> s1 == s2  # For string comparison 
False
>>> sorted(list(s1)) == sorted(list(s2)) # For comparing if they have same characters. 
True
>>> sorted(list(s1))
[' ', ' ', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
>>> sorted(list(s2))
[' ', ' ', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']

回答4:

Something like this:

if string1 == string2:
    print 'they are the same'

update: if you want to see if each sub-string may exist in the other:

elem1 = [x for x in string1.split()]
elem2 = [x for x in string2.split()]

for item in elem1:
    if item in elem2:
        print item

回答5:

Equality in direct comparing:

string1 = "sample"
string2 = "sample"

if string1 == string2 :
    print("Strings are equal with text : ", string1," & " ,string2)
else :
    print ("Strings are not equal")

Equality in character sets:

string1 = 'abc def ghi'
string2 = 'def ghi abc'

set1 = set(string1.split(' '))
set2 = set(string2.split(' '))

print set1 == set2

if string1 == string2 :
    print("Strings are equal with text : ", string1," & " ,string2)
else :
    print ("Strings are not equal")

回答6:

For that, you can use default difflib in python

from difflib import SequenceMatcher

def similar(a, b):
    return SequenceMatcher(None, a, b).ratio()

then call similar() as

similar(string1, string2)

it will return compare as ,ratio >= threshold to get match result

回答7:

I am going to provide several solutions and you can choose the one that meets your needs:

1) If you are concerned with just the characters, i.e, same characters and having equal frequencies of each in both the strings, then use:

''.join(sorted(string1)).strip() == ''.join(sorted(string2)).strip()

2) If you are also concerned with the number of spaces (white space characters) in both strings, then simply use the following snippet:

sorted(string1) == sorted(string2)

3) If you are considering words but not their ordering and checking if both the strings have equal frequencies of words, regardless of their order/occurrence, then can use:

sorted(string1.split()) == sorted(string2.split())

4) Extending the above, if you are not concerned with the frequency count, but just need to make sure that both the strings contain the same set of words, then you can use the following:

set(string1.split()) == set(string2.split())

回答8:

I think difflib is a good library to do this job

   >>>import difflib 
   >>> diff = difflib.Differ()
   >>> a='he is going home'
   >>> b='he is goes home'
   >>> list(diff.compare(a,b))
     ['  h', '  e', '   ', '  i', '  s', '   ', '  g', '  o', '+ e', '+ s', '- i', '- n', '- g', '   ', '  h', '  o', '  m', '  e']
    >>> list(diff.compare(a.split(),b.split()))
      ['  he', '  is', '- going', '+ goes', '  home']

回答9:

open both of the files then compare them by splitting its word contents;

log_file_A='file_A.txt'

log_file_B='file_B.txt'

read_A=open(log_file_A,'r')
read_A=read_A.read()
print read_A

read_B=open(log_file_B,'r')
read_B=read_B.read()
print read_B

File_A_set = set(read_A.split(' '))
File_A_set = set(read_B.split(' '))
print File_A_set == File_B_set

回答10:

If you want a really simple answer:

s_1 = "abc def ghi"
s_2 = "def ghi abc"
flag = 0
for i in s_1:
    if i not in s_2:
        flag = 1
if flag == 0:
    print("a == b")
else:
    print("a != b")

回答11:

Try to covert both strings to upper or lower case. Then you can use == comparison operator.

回答12:

This is a pretty basic example, but after the logical comparisons (==) or string1.lower() == string2.lower(), maybe can be useful to try some of the basic metrics of distances between two strings.

You can find examples everywhere related to these or some other metrics, try also the fuzzywuzzy package (https://github.com/seatgeek/fuzzywuzzy).

import Levenshtein
import difflib

print(Levenshtein.ratio('String1', 'String2'))
print(difflib.SequenceMatcher(None, 'String1', 'String2').ratio())

回答13:

If you just need to check if the two strings are exactly same,

text1 = 'apple'

text2 = 'apple'

text1 == text2

The result will be

True

If you need the matching percentage,

import difflib

text1 = 'Since 1958.'

text2 = 'Since 1958'

output = str(int(difflib.SequenceMatcher(None, text1, text2).ratio()*100))

Matching percentage output will be,

'95'

来源：https://stackoverflow.com/questions/21903842/how-do-i-compare-two-strings-in-python