Python Program to check whether all elements in a string list are numeric

Given a list that contains only string elements the task here is to write a Python program to check if all of them are numeric or not. If all are numeric return True otherwise, return False.

Input : test_list = ["434", "823", "98", "74"]
Output : True
Explanation : All Strings are digits.

Input : test_list = ["434", "82e", "98", "74"]
Output : False
Explanation : e is not digit, hence verdict is False.

Method 1 : Using all(), isdigit() and generator expression

In this, we check for numbers from isdigit(). all() is used to check for all strings to be number, and iteration for each string is done using generator expression.

Example:

Python3

# initializing list
test_list = ["434", "823", "98", "74"]

# printing original list
print("The original list is : " + str(test_list))

# checking all elements to be numeric using isdigit()
res = all(ele.isdigit() for ele in test_list)

# printing result
print("Are all strings digits ? : " + str(res))

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time Complexity: O(n)

Auxiliary Space: O(n)

Method 2 : Using  all(), isdigit() and map()

In this, we extend test logic to each string using map(), rather than generator expression. Rest all the functionalities are performed similarly to the above method.

Example:

Python3

# initializing list
test_list = ["434", "823", "98", "74"]

# printing original list
print("The original list is : " + str(test_list))

# checking all elements to be numeric using isdigit()
# map() to extend to each element
res = all(map(str.isdigit, test_list))

# printing result
print("Are all strings digits ? : " + str(res))

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time Complexity: O(n)

Auxiliary Space: O(n)

Method 3 : Using isnumeric() and len() methods

Python3

# initializing list
test_list = ["434", "82e", "98", "74"]

# printing original list
print("The original list is : " + str(test_list))

# checking all elements to be numeric using isdigit()
c=0
for i in test_list:
    if i.isnumeric():
        c+=1
res=False
if(c==len(test_list)):
    res=True

# printing result
print("Are all strings digits ? : " + str(res))

Output

The original list is : ['434', '82e', '98', '74']
Are all strings digits ? : False

Time Complexity: O(n)

Auxiliary Space: O(n)

Method 4 : Using replace() and len() methods

Python3

# Python Program to check whether all elements in a string list are numeric
# initializing list
test_list = ["434", "82e", "98", "74"]

# printing original list
print("The original list is : " + str(test_list))

# checking all elements to be numeric using isdigit()
c = 0
numbers = "0123456789"
for i in test_list:
    for j in numbers:
        i = i.replace(j, "")
    if(len(i) == 0):
        c += 1
res = False
if(c == len(test_list)):
    res = True

# printing result
print("Are all strings digits ? : " + str(res))

Output

The original list is : ['434', '82e', '98', '74']
Are all strings digits ? : False

Time Complexity: O(n*n)
Auxiliary Space: O(n)

Method 5 : Using filter()+list()+lambda functions

Python3

# initializing list
test_list = ["434", "823", "98", "74"]

# printing original list
print("The original list is : " + str(test_list))

# checking all elements to be numeric using isdigit()
res = list(filter(lambda x: x.isdigit(), test_list))

if(len(res) == len(test_list)):
    res = True
else:
    res = False
# printing result
print("Are all strings digits ? : " + str(res))

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time Complexity: O(n)

Auxiliary Space: O(n)

Method 6 : Using reduce()

Python3

from functools import reduce
from operator import and_
test_list = ["434", "823", "98", "74"]
print("The original list is : " + str(test_list))
res = reduce(and_, (string.isdigit() for string in test_list))
print("Are all strings digits ? : " + str(res))
#This code is contributed by Jyothi pinjala.

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time Complexity: O(n)

Auxiliary Space: O(1)

Method 7:Using for loop

Python3

test_list = ["434", "823", "98", "74"]
print("The original list is : " + str(test_list))
for string in test_list:
    if not string.isdigit():
        res = False
        break
else:
    res = True
print("Are all strings digits ? : " + str(res))
#This code is contributed by Vinay Pinjala.

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time complexity: O(n)

Auxiliary Space: O(1)

Method 8: Using loop +try and except  method.

Python3

test_list = ["434", "823", "98", "74"]
print("The original list is : " + str(test_list))
for i in test_list:
  try:
    int(i)
    res=True
  except:
    res=False
print("Are all strings digits ? : " + str(res))
#This code is contributed by tvsk.

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time complexity: O(n)

Auxiliary Space: O(1)

Method 9: Using re.match() method

Approach

1. Initiate a for loop to traverse test_list, variable c=0
2. Check whether each string is numeric or not using regular expression ^[0-9]+$ and method re.match() if yes increment c by 1
3. If c equals to length of test_list then all strings have digits, set res to True or else False
4. Display res

Python3

import re

# initializing list
test_list = ["434", "823", "98", "74"]

# printing original list
print("The original list is : " + str(test_list))

# checking all elements to be
# numeric using isdigit()
c = 0
for i in test_list:
    if re.match('^[0-9]+$', i):
        c += 1

res = c == len(test_list)

# printing result
print("Are all strings digits ? : " + str(res))

Output

The original list is : ['434', '823', '98', '74']
Are all strings digits ? : True

Time Complexity: O(N) N – length of test_list

Auxiliary Space: O(1) because we used single variable res to store result