Python Maximum String Value Length

How to find the length of the maximum string value in Python? The length of the maximum string is determined by the amount of available memory in the system. This means that a string can allow as long as your system’s available memory. To find the maximum string value length in a list or any iterable, you can use the max() function along with a key function that returns the length of each string.

1. Quick Examples of Finding Length of Maximum String

If you are in a hurry, below are some quick examples of finding the length of a maximum string value.


# Quick examples of maximum string value length

# Example 1: Maximum length of string value
maximum_length = sys.maxsize

# Example 2: Get maximum length of string value 
# using max() and len() 
mystring = ["Spark","Python","Hadoop","Hyperion"]
max_length = max(len(string) for string in mystring)

# Initializing list of dictionaries
mystring = [{'Courses' :  "Python", 'fee' : 2000}, {'Courses' :  "PySpark", 'fee' : 3000}, {'Courses' : "Java", 'fee' : 2500}]

# Example 3: Maximum String value length of Key of dictionary
# Using max() + len() 
filter_key = 'Courses'
temp = (sub[filter_key] for sub in mystring)
max_length = max(len(ele) for ele in temp if ele is not None)

# Example 4: Using list comprehension + len() + max()
filter_key = 'Courses'
max_length = len(max(mystring, key = lambda sub: len(sub[filter_key])
                if sub[filter_key] is not None else 0)[filter_key])

# Example 5: Using for loop
# Find the maximum String value length of the Key of dict
filter_key = 'Courses'
max_length = 0
for sub_dict in mystring:
    if filter_key in sub_dict:
        value = sub_dict[filter_key]
        if value is not None and len(value) > max_length:
            max_length = len(value)

2. What is the Length of Maximum String in Python

The maximum length of a string depends on the underlying system and available resources. However, the theoretical maximum length of a string in Python is sys.maxsize, which is the maximum value for a signed integer on the platform. You can check the maximum length on your system using the sys.maxsize constant.

Note that the actual maximum length you can practically use may be limited by factors such as available memory or specific implementation details of Python.


import sys
# Maximum length of string
maximum_length = sys.maxsize
print("The maximum string length is:", maximum_length)

Yields below output.

3. Find the Maximum String Value length

You can find the length of the maximum string value to use a combination of <a href="https://sparkbyexamples.com/python/python-list-max-function/">max()</a>, and len(). For example, you can use a list comprehension to iterate over each string in the strings list(mystring) and obtain its length using len(). The resulting list of string lengths is then passed as an argument to the max() function to find the maximum length.


# Initialize the list of strings
mystring = ["Spark","Python","Hadoop","Hyperion"]
print("Original list: ", mystring)

# Get maximum string value length 
max_length = max(len(string) for string in mystring)
print("The maximum string length is:", max_length)

Yields below output.

4. Find the Maximum String Value Length of the Dictionary Key

You can find the maximum length of the string values for a specific key in a Python dictionary.

4.1 Using max() & len()

Using max() with len() & for loop you can find the length of the highest string value. For example, you can calculate the maximum string length of the ‘Courses‘ key in the list of dictionaries, mystring. You can use for loop to iterate over each dictionary mystring and extract the value associated with the ‘Courses‘ key, and finds the maximum length among all non-null values. In this specific case, the maximum string length of the ‘Courses‘ key is determined to be 7, which corresponds to the length of the string “PySpark“.


# Maximum String value length of Key of dictionary
# Using max() + len()
# Initializing list of dictionaries
mystring = [{'Courses' :  "Python", 'fee' : 2000},
            {'Courses' :  "PySpark", 'fee' : 3000},
            {'Courses' : "Java", 'fee' : 2500}]
print("Original list:", mystring)
 
# Initializing Key
filter_key = 'Courses'
temp = (sub[filter_key] for sub in mystring)
max_length = max(len(ele) for ele in temp if ele is not None)
print("The maximum string length of key is:", max_length)

# Output:
# Original list: [{'Courses': 'Python', 'fee': 2000}, {'Courses': 'PySpark', 'fee': 3000}, {'Courses': 'Java', 'fee': 2500}]
# The maximum string length of key is: 7

4.2. Using list comprehension + len() + max() Function + Lambda

You can also be using a one-liner approach with list comprehension, len(), and max() to find the maximum string length of the ‘Courses‘ key. For example, calculates the maximum string length of the ‘Courses‘ key in the list of dictionaries, mystring, using a slightly different approach. It utilizes the max() function with a lambda function as the key argument to determine the dictionary with the longest string value for the 'Courses' key. Then, it retrieves the length of that value to obtain the maximum string length.


# Maximum String value length of Key of dictionary
# Using list comprehension+ max() + len()
# Initializing Key
filter_key = 'Courses'
max_length = len(max(mystring, key = lambda sub: len(sub[filter_key])
                if sub[filter_key] is not None else 0)[filter_key])
print("The maximum string length of key is:", max_length)

Yields the same output as above.

4.3. Using For Loop

You can find the maximum string value length of a specific key using a for loop. For example, utilizes a for loop to find the maximum string length of the ‘Courses‘ key in the list of dictionaries mystring. The loop iterates over each dictionary, checks if the 'Courses' key exists, and if so, updates the max_length variable if the length of the corresponding value is greater than the current maximum length.


# Initializing Key
filter_key = 'Courses'
 
# Using for loop
# Find maximum String value length of dictionary Key
max_length = 0
for sub_dict in mystring:
    if filter_key in sub_dict:
        value = sub_dict[filter_key]
        if value is not None and len(value) > max_length:
            max_length = len(value)
print("The maximum string length of key is:", max_length)

Yields the same output as above.

Conclusion

In this article, I have explained how to find the maximum string value length in Python by using sys.maxsize, max(), len(), for loop, and list comprehension + len() + max() functions with examples.

Happy Learning !!