Given a string, the task is to find the frequencies of all the characters in that string and return a dictionary with key
as the character and its value
as its frequency in the given string.
Method #1 : Naive method
Simply iterate through the string and form a key in dictionary of newly occurred element or if element is already occurred, increase its value by 1.
test_str
=
"GeeksforGeeks"
all_freq
=
{}
for
i
in
test_str:
if
i
in
all_freq:
all_freq[i]
+
=
1
else
:
all_freq[i]
=
1
print
[
"Count of all characters in GeeksforGeeks is :\n "
+
str
[all_freq]]
Output :
Count of all characters in GeeksforGeeks is : {'r': 1, 'e': 4, 'k': 2, 'G': 2, 's': 2, 'f': 1, 'o': 1}
Method #2 : Using collections.Counter[]
The most suggested method that could be used to find all occurrences is this method, this actually gets all element frequency and could also be used to print single element frequency if required.
from
collections
import
Counter
test_str
=
"GeeksforGeeks"
res
=
Counter[test_str]
print
[
"Count of all characters in GeeksforGeeks is :\n "
+
str
[res]]
Output :
Count of all characters in GeeksforGeeks is : Counter[{'e': 4, 's': 2, 'k': 2, 'G': 2, 'o': 1, 'r': 1, 'f': 1}]
Method #3 : Using dict.get[]
get[]
method is used to check the previously occurring character in string, if its new, it
assigns 0 as initial and appends 1 to it, else appends 1 to previously holded value of that element in dictionary.
test_str
=
"GeeksforGeeks"
res
=
{}
for
keys
in
test_str:
res[keys]
=
res.get[keys,
0
]
+
1
print
[
"Count of all characters in GeeksforGeeks is : \n"
+
str
[res]]
Output :
Count of all characters in GeeksforGeeks is : {'k': 2, 'e': 4, 's': 2, 'G': 2, 'f': 1, 'r': 1, 'o': 1}
Method #4 : Using set[] + count[]
count[]
coupled with set[]
can also achieve this task, in this we just iterate over the set converted string and get the count of each character in original string and assign that element with that value counted using count[]
.
test_str
=
"GeeksforGeeks"
res
=
{i : test_str.count[i]
for
i
in
set
[test_str]}
print
[
"The count of all characters in GeeksforGeeks is :\n "
+
str
[res]]
Output :
Count of all characters in GeeksforGeeks is : {'G': 2, 's': 2, 'k': 2, 'e': 4, 'o': 1, 'r': 1, 'f': 1}