In this post, we are going to learn how to compare strings in Python by ignoring the case. We can compare string in python using equality operator(==) or comparison operator (<,>,<=,>=,!=).We are going to perform string comparison using these ways.
Compare string using == operator
we are performing string comparison using the == operator each character of both strings will compare character by character. == operator returns True if both strings are equal else returns false.
Example:Compare String using == operator
greet_str = "Hi how are you"
greet_str2 = "Hi how are you"
if greet_str == greet_str2:
print('greet_str and greet_str2 are same')
else:
print('greet_str and greet_str2 not same')
Output
greet_str and greet_str2 are same
Compare String Using IS vs == operator
Equal operator(==) compares variables based on their values mainly used for immutable type.
Is operator: It compares variables based on object id. If two variables referring the same object then they are equal. IS used to compare the objects.
var_a = 'rat'
var_b = 'rat'
if var_a is var_b:
print('var_a and var_b are same')
else:
print('var_a and var_b not same')
print('\nID of both is same:')
print(id(var_a))
print(id(var_b))
# now changing value of
print('\n---After change value of var_b:---')
var_b = "rat is".split()[0]
print('\nvalue of var_b:',var_b)
print('\nvalues is same but ID of both is not same:\n')
print(id(var_a))
print(id(var_b))
#compare change value using is and == operator
print('\ncompare using is operator:\n')
if var_a is var_b:
print('var_a and var_b are same\n')
else :
print('var_a and var_b are not same\n')
#compare change value using == operator
print('compare using == operator :\n')
if var_a == var_b:
print('var_a and var_b are same')
Output
var_a and var_b are same
ID of both is same:
140037812604272
140037812604272
---After change value of var_b:---
value of var_b: rat
values is same but ID of both is not same:
140037812604272
140037812604592
compare using is operator:
var_a and var_b are not same
compare using == operator :
var_a and var_b are same
Compare strings using != operator
In this example, we are comparing string using the != ((not equal)operator. != operator return True if both strings are not equal Else return False.
greet_str = "Hi how are you"
greet_str2 = "Hi how are you"
if greet_str != greet_str2:
print('greet_str and greet_str2 not same')
else:
print('greet_str and greet_str2 are same')
Output
greet_str and greet_str2 are same
Compare strings using comparison operator
The string is compared character by character if the characters do not match then the character’s Unicode value is compared.
Let understand how to compare string using comparison operators
str = "Hi how are you"
str2 = "how are you"
print (str<str2)
print (str>str2)
print (str<=str2)
print (str>=str2)
Output
True
False
True
False
Compare string in Python by ignoring case
if we have to compare two strings, which are different by cases, contain the characters of different cases. In this case, we ignore the case by converting the string in lower case or in the upper case finally compares the string using the == operator.
Compare string by ignore case
greet_str = "HI how are YOU"
greet_str2 = "Hi how Are you"
if greet_str.upper()== greet_str2.upper():
print('greet_str and greet_str2 are same')
else:
print('greet_str and greet_str2 not same')
Output
greet_str and greet_str2 are same
Compare strings using Regex by ignorance case
In this code example we are using the regular expression to compare two strings,if the string are same then it return True else False.
import re
greet_str = "HI how are YOU"
greet_str2 = "Hi how are you"
if (re.search(greet_str,greet_str2,re.IGNORECASE)):
print('greet_str and greet_str2 are same')
else:
print('greet_str and greet_str2 not same')
Output
greet_str and greet_str2 are same
Compare List of string Using Regex by ignore-case
To use Regular Expression(regex) first import re module and define a pattern, pattern matches the string in str_list that contain the characters or digits either lower or upper case.
import re
str_list = ['The96500','has123','had','HELLO123']
pattern = re.compile("(?i)[A-Z][0-9]\w+")
for str in str_list:
if pattern.search(str):
print (" Matched string :" ,str)
Output
Matched string : The96500
Matched string : has123
Matched string : HELLO123
Conclusion
We have understood different ways to Compare strings in the Python ignorance case.