Python: Count the number of occurrences in a list

Last update on May 28 2022 12:51:21 (UTC/GMT +8 hours)

Python Basic: Exercise-22 with Solution

Write a Python program to count the number 4 in a given list.

Pictorial Presentation:

Sample Solution:-

Python Code:

def list_count_4(nums):
  count = 0  
  for num in nums:
    if num == 4:
      count = count + 1

  return count

print(list_count_4([1, 4, 6, 7, 4]))
print(list_count_4([1, 4, 6, 4, 7, 4]))

Sample Output:

2                                                                                                             
3

Flowchart:

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Previous: Write a Python program to find whether a given number (accept from the user) is even or odd, print out an appropriate message to the user.
Next: Write a Python program to get the n (non-negative integer) copies of the first 2 characters of a given string. Return the n copies of the whole string if the length is less than 2.

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Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

The os and os.path modules.
The __file__ constant
os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
os.path.dirname(path) (returns "the directory name of pathname path")
os.getcwd() (returns "a string representing the current working directory")
os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m