# Python – Case Insensitive string counter

• Last Updated : 21 Sep, 2022

Given a list of strings, find the frequency of strings case insensitive.

```Input : test_list = ["Gfg", "Best", "GFG", "is", "IS", "BEST"]
Output : {'gfg': 2, 'best': 2, 'is': 2}
Explanation : All occur twice. ```
```Input : test_list = ["Gfg", "gfg", "GFG"]
Output : {'gfg': 3}
Explanation : Only "gfg" 3 occurrences.```

Method 1: Using defaultdict() + lower()

In this, we perform lower() to all the strings, before mapping in defaultdict. This ensures case insensitivity while mapping and cumulating frequency.

## Python3

 `# Python3 code to demonstrate working of``# Strings Frequency (Case Insensitive)``# Using defaultdict() + lower()` `from` `collections ``import` `defaultdict` `# initializing list``test_list ``=` `[``"Gfg"``, ``"Best"``, ``"best"``, ``"gfg"``, ``"GFG"``, ``"is"``, ``"IS"``, ``"BEST"``]` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))` `res ``=` `defaultdict(``int``)` `for` `ele ``in` `test_list:` `    ``# lowercasing to cater for Case Insensitivity``    ``res[ele.lower()] ``+``=` `1` `# printing result``print``(``"Strings Frequency : "` `+` `str``(``dict``(res)))`

Output

```The original list is : ['Gfg', 'Best', 'best', 'gfg', 'GFG', 'is', 'IS', 'BEST']
Strings Frequency : {'gfg': 3, 'best': 3, 'is': 2}```

Time Complexity: O(n)

Auxiliary Space: O(n)

Method 2: Using count() method

## Python3

 `# Python3 code to demonstrate working of``# Strings Frequency (Case Insensitive)` `# initializing list``test_list ``=` `[``"Gfg"``, ``"Best"``, ``"best"``, ``"gfg"``, ``"GFG"``, ``"is"``, ``"IS"``, ``"BEST"``]` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))``x ``=` `[]``res ``=` `dict``()``for` `i ``in` `test_list:``    ``x.append(i.lower())``a ``=` `list``(``set``(x))``for` `i ``in` `a:``    ``res[i] ``=` `x.count(i)` `# printing result``print``(``"Strings Frequency : "` `+` `str``(``dict``(res)))`

Output

```The original list is : ['Gfg', 'Best', 'best', 'gfg', 'GFG', 'is', 'IS', 'BEST']
Strings Frequency : {'best': 3, 'is': 2, 'gfg': 3}```

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