How do you count positions in python?

You could use combination of zip and Counter

a = ("abcd")
b = ("a5c1")
c = ("b51d")

from collections import Counter

zippedList = list(zip(a,b,c))
print("zipped: {}".format(zippedList))


final = ""
for x in zippedList:
    countLetters = Counter(x)
    print(countLetters)
    final += countLetters.most_common(3)[0][0]

print("output: {}".format(final))

output:

zipped: [('a', 'a', 'b'), ('b', '5', '5'), ('c', 'c', '1'), ('d', '1', 'd')]
Counter({'a': 2, 'b': 1})
Counter({'5': 2, 'b': 1})
Counter({'c': 2, '1': 1})
Counter({'d': 2, '1': 1})
output: a5cd


Suppose we have a list of numbers called nums, we have to find the number of elements that are present in the correct indices, when the list was to be sorted.

So, if the input is like [2, 8, 4, 5, 11], then the output will be 2, as the elements 2 and 11 are in their correct positions. The sorted sequence will be [2, 4, 5, 8, 11]

To solve this, we will follow these steps −

  • s := sort the list nums
  • count := 0
  • for i in range 0 to size of nums, do
    • if s[i] is same as nums[i], then
      • count := count + 1
  • return count

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, nums):
      s = sorted(nums)
      count = 0
      for i in range(len(nums)):
         if s[i] == nums[i]:
            count += 1
      return count
ob = Solution()
print(ob.solve([2, 8, 4, 5, 11]))

Input

[2, 8, 4, 5, 11]

Output

2

How do you count positions in python?

Updated on 05-Oct-2020 06:39:45

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The count() is a built-in function in Python. It will return the total count of a given element in a string. The counting begins from the start of the string till the end. It is also possible to specify the start and end index from where you want the search to begin.

In this Python tutorial, you will learn:

  • Python count
  • The syntax for PythonString Count()
  • Example 1: Count Method on a String
  • Example 2: Count occurrence of a character in a given string
  • Example 3: Count occurrence of substring in a given string

The syntax for PythonString Count()

Python count function syntax:

string.count(char or substring, start, end)

Parameters of Python Syntax

  • Char or substring: You can specify a single character or substring you are wants to search in the given string. It will return you the count of the character or substring in the given string.
  • start : (optional) It indicates the start index from where the search will begin. If not given, it will start from 0. For example, you want to search for a character from the middle of the string. You can give the start value to your count function.
  • end: (optional) It indicates the end index where the search ends. If not given, it will search till the end of the list or string given. For example, you don’t want to scan the entire string and limit the search till a specific point you can give the value to end in your count function, and the count will take care of searching till that point.

ReturnValue

The count() method will return an integer value, i.e., the count of the given element from the given string. It returns a 0 if the value is not found in the given string.

Example 1: Count Method on a String

The following example shows the working of count() function on a string.

str1 = "Hello World"
str_count1 = str1.count('o')  # counting the character “o” in the givenstring
print("The count of 'o' is", str_count1)

str_count2 = str1.count('o', 0,5)
print("The count of 'o' usingstart/end is", str_count2)

Output:

The count of 'o' is 2
The count of 'o' usingstart/end is 1

Example 2: Count occurrence of a character in a given string

The following example shows the occurrence of a character in a given string as well as in by using the start/end index.

str1 = "Welcome to Guru99 Tutorials!"
str_count1 = str1.count('u')  # counting the character “u” in the given string
print("The count of 'u' is", str_count1)

str_count2 = str1.count('u', 6,15)
print("The count of 'u' usingstart/end is", str_count2)

Output:

The count of 'u' is 3
The count of 'u' usingstart/end is 2

Example 3: Count occurrence of substring in a given string

Following example shows the occurrence of substring in a givenstring as well as usingstart/endindex.

str1 = "Welcome to Guru99 - Free Training Tutorials and Videos for IT Courses"
str_count1 = str1.count('to') # counting the substring “to” in the givenstring
print("The count of 'to' is", str_count1)
str_count2 = str1.count('to', 6,15)
print("The count of 'to' usingstart/end is", str_count2)

Output:

The count of 'to' is 2
The count of 'to' usingstart/end is 1

Summary:

  • The count() is a built-in function in Python. It will return you the count of a given element in a list or a string.
  • In the case of a string, the counting begins from the start of the string till the end. It is also possible to specify the start and end index from where you want the search to begin.
  • The count() method returns an integer value.

How do you find the position of something in Python?

To find a position of the particular element you can use the index() method of List class with the element passed as an argument. An index() function returns an integer (position) of the first match of the specified element in the List.

Is there a count method in Python?

Count() is a Python built-in function that returns the number of times an object appears in a list. The count() method is one of Python's built-in functions. It returns the number of times a given value occurs in a string or a list, as the name implies.

How do you use the count function in Python?

The count() method returns the number of occurrences of a substring in the given string..
substring - string whose count is to be found..
start (Optional) - starting index within the string where search starts..
end (Optional) - ending index within the string where search ends..

How do you count inputs in Python?

Python String has got an in-built function – string. count() method to count the occurrence of a character or a substring in the particular input string. The string. count() method accepts a character or a substring as an argument and returns the number of times the input substring happens to appear in the string.

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