{"id":4008,"date":"2020-03-12T19:23:18","date_gmt":"2020-03-12T19:23:18","guid":{"rendered":"https:\/\/www.askpython.com\/?p=4008"},"modified":"2023-02-16T19:57:13","modified_gmt":"2023-02-16T19:57:13","slug":"generate-random-strings-in-python","status":"publish","type":"post","link":"https:\/\/www.askpython.com\/python\/examples\/generate-random-strings-in-python","title":{"rendered":"How to Generate Random Strings in Python"},"content":{"rendered":"\n

In this article, we’ll take a look at how we can generate random strings in Python. As the name suggests, we need to generate a random sequence of characters, it is suitable for the random<\/code> module.<\/p>\n\n\n\n

There are various approaches here, so we’ll start from the most intuitive one; using randomized integers.<\/p>\n\n\n\n

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Build a string from a random integer sequence<\/h2>\n\n\n\n

As you may know, the chr(integer)<\/code> maps the integer to a character, assuming it lies within the ASCII limits. (Taken to be 255<\/code> for this article)<\/p>\n\n\n\n

We can use this mapping to scale any integer to the ASCII character level, using chr(x)<\/code>, where x<\/code> is generated randomly.<\/p>\n\n\n

\nimport random\n\n# The limit for the extended ASCII Character set\nMAX_LIMIT = 255\n\nrandom_string = ''\n\nfor _ in range(10):\n    random_integer = random.randint(0, MAX_LIMIT)\n    # Keep appending random characters using chr(x)\n    random_string += (chr(random_integer))\n\nprint(random_string, len(random_string))\n\n<\/pre><\/div>\n\n\n
Sample Output<\/strong><\/p>\n\n\n
\n\u00f0|\u00d2R:\n     R\u00e8 10\n<\/pre><\/div>\n\n\n
Here, while the length of the string seems to be 10 characters, we get some weird characters along with newlines, spaces, etc.<\/p>\n\n\n\n
This is because we considered the entire ASCII Character set.<\/p>\n\n\n\n
If we want to deal with only English alphabets, we can use their ASCII values.<\/p>\n\n\n
\nimport random\n\nrandom_string = ''\n\nfor _ in range(10):\n    # Considering only upper and lowercase letters\n    random_integer = random.randint(97, 97 + 26 - 1)\n    flip_bit = random.randint(0, 1)\n    # Convert to lowercase if the flip bit is on\n    random_integer = random_integer - 32 if flip_bit == 1 else random_integer\n    # Keep appending random characters using chr(x)\n    random_string += (chr(random_integer))\n\nprint(random_string, len(random_string))\n\n<\/pre><\/div>\n\n\n
Sample Output<\/strong><\/p>\n\n\n
\nwxnhvYDuKm 10\n<\/pre><\/div>\n\n\n
As you can see, now we have only upper and lowercase letters.<\/p>\n\n\n\n
But we can avoid all this hassle, and have Python do the work for us. Python has given us the string<\/code> module for exactly this purpose!<\/p>\n\n\n\n
Let’s look at how we can do the same this, using just a couple of lines of code!<\/p>\n\n\n\n
Generate Random Strings in Python using the string module<\/h2>\n\n\n\n
The list of characters used by Python strings<\/a> is defined here, and we can pick among these groups of characters.<\/p>\n\n\n\n
We’ll then use the random.choice()<\/code> method to randomly choose characters, instead of using integers, as we did previously.<\/p>\n\n\n\n
Let us define a function random_string_generator()<\/code>, that does all this work for us. This will generate a random string, given the length of the string, and the set of allowed characters to sample from.<\/p>\n\n\n
\nimport random\nimport string\n\ndef random_string_generator(str_size, allowed_chars):\n    return ''.join(random.choice(allowed_chars) for x in range(str_size))\n\nchars = string.ascii_letters + string.punctuation\nsize = 12\n\nprint(chars)\nprint('Random String of length 12 =', random_string_generator(size, chars))\n<\/pre><\/div>\n\n\n
Here, we have specified the allowed list of characters as the string.ascii_letters<\/code> (upper and lowercase letters), along with string.punctuation<\/code> (all punctuation marks).<\/p>\n\n\n\n
Now, our main function was only 2 lines, and we could randomly choose a character, using random.choice(set)<\/code>.<\/p>\n\n\n\n
Sample Output<\/strong><\/p>\n\n\n
\nabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&'()*+,-.\/:;<=>?@[\\]^_`{|}~\nRandom String of length 12 = d[$Om{;#cjue\n<\/pre><\/div>\n\n\n
We have indeed generated a random string, and the string<\/code> module allows easy manipulations between character sets!<\/p>\n\n\n\n
Make the random generation more secure<\/h3>\n\n\n\n
While the above random generation method works, if you want to make your function be more cryptographically secure, use the random.SystemRandom()<\/code> function.<\/p>\n\n\n\n
An example random generator function is shown below:<\/p>\n\n\n
\nimport random\nimport string\n\noutput_string = ''.join(random.SystemRandom().choice(string.ascii_letters + string.digits) for _ in range(10))\n\nprint(output_string)\n<\/pre><\/div>\n\n\n
Output<\/strong><\/p>\n\n\n
\niNsuInwmS8\n<\/pre><\/div>\n\n\n
This ensures that your string generation is cryptographically secure.<\/p>\n\n\n\n
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Random UUID Generation<\/h2>\n\n\n\n
If you want to generate a random UUID<\/a> String, the uuid<\/code> module is helpful for this purpose.<\/p>\n\n\n
\nimport uuid\n\n# Generate a random UUID\nprint('Generated a random UUID from uuid1():', uuid.uuid1())\nprint('Generated a random UUID from uuid4():', uuid.uuid4())\n<\/pre><\/div>\n\n\n
Sample Output<\/strong><\/p>\n\n\n
\nGenerated a random UUID from uuid1(): af5d2f80-6470-11ea-b6cd-a73d7e4e7bfe\nGenerated a random UUID from uuid4(): 5d365f9b-14c1-49e7-ad64-328b61c0d8a7\n<\/pre><\/div>\n\n\n
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Conclusion<\/h2>\n\n\n\n
In this article, we learned how we could generate random strings in Python, with the help of the random<\/code> and string<\/code> modules.<\/p>\n\n\n\n
References<\/h2>\n\n\n\n