Summary: Split the string using split and then use len to count the results.

Minimal Example

print("Result Count: ", len('one,two,three'.split(',')))

# Result Count: 3

Problem Formulation

Problem: Given a string. How will you split the string and find the number of split strings? Can you store the split strings into different variables?

Example

# Given String

text = '366NX-BQ62X-PQT9G-GPX4H-VT7TX'

# Expected Output:

Number of split strings: 5

key_1 = 366NX

key_2 = BQ62X

key_3 = PQT9G

key_4 = GPX4H

key_5 = VT7TX

In the above problem, the delimiter used to split the string is “-“. After splitting five substrings can be extracted. Therefore, you need five variables to store the five substrings. Can you solve it?

Solution

Splitting the string and counting the number of results is a cakewalk. All you have to do is split the string using the split() function and then use the len method upon the resultant list returned by the split method to get the number of split strings present.

Code:

text = '366NX-BQ62X-PQT9G-GPX4H-VT7TX'

# splitting the string using - as separator

res = text.split('-')

# length of split string list

x = len(res)

print("Number of split strings: ", x)

Approach 1

• The idea here is to find the length of the results and then use this length to create another list containing all the variable names as items within it. This can be done with a simple for loop.
• Now, you have two lists. One that stores the split strings and another that stores the variable names that will store the split strings.
• So, you can create a dictionary out of the two lists such that the keys in this dictionary will be the items of the list containing the variable names and the values in this dictionary will be the items of the list containing the split strings. Read: How to Convert Two Lists Into A Dictionary

Code:

text = '366NX-BQ62X-PQT9G-GPX4H-VT7TX'

# splitting the string using - as separator

res = text.split('-')

# length of split string list

x = len(res) # Naming and storing variables and values

name = []

for i in range(1, x+1): name.append('key_'+str(i)) d = dict(zip(name, res))

for key, value in d.items(): print(key, "=", value)

Approach 2

Almost all modules have a special attribute known as __dict__ which is a dictionary containing the module’s symbol table. It is essentially a dictionary or a mapping object used to store an object’s (writable) attributes.

So, you can create a class and then go ahead create an instance of this class which can be used to set different attributes. Once you split the given string and also create the list containing the variable names (as done in the previous solution), you can go ahead and zip the two lists and use the setattr() method to assign the variable and their values which will serve as the attributes of the previously created class object. Once, you have set the attributes (i.e. the variable names and their values) and attached them to the object, you can access them using the built-in __dict__ as object_name.__dict__

Code:

text = '366NX-BQ62X-PQT9G-GPX4H-VT7TX'

# splitting the string using - as separator

res = text.split('-')

# length of split string list

x = len(res)

print("Number of split strings: ", x) # variable creation and value assignment

name = []

for i in range(1, x + 1): name.append('key_' + str(i)) class Record(): pass r = Record() for name, value in zip(name, res): setattr(r, name, value)

print(r.__dict__) for key, value in r.__dict__.items(): print(key, "=", value)

Approach 3

Caution: This solution is not recommended unless this is the only option left. I have mentioned this just because it solves the purpose. However, it is certainly not the best way to approach the given problem.

Code:

text = '366NX-BQ62X-PQT9G-GPX4H-VT7TX'

# splitting the string using - as separator

res = text.split('-')

# length of split string list

x = len(res)

print("Number of split strings: ", x)

name = []

for i in range(1, x + 1): name.append('key_' + str(i)) for idx, value in enumerate(res): globals()["key_" + str(idx + 1)] = value

print(globals())

x = 0

for i in reversed(globals()): print(i, "=", globals()[i]) x = x+1 if x == 5: break

Explanation: globals() function returns a dictionary containing all the variables in the global scope with the variable names as the key and the value assigned to the variable will be the value in the dictionary. You can reference this dictionary and add new variables by string name (globals()['a'] = 'b' sets variable a equal to "b"), however this is generally a terrible thing to do.

Since global returns a dictionary containing all the variables in the global scope, a workaround to get only the variables we assigned is to extract the last “N” key-value pairs from this dictionary where “N” is the length of the split string list.

Conclusion

I hope the solutions mentioned in this tutorial have helped you. Please stay tuned and subscribe for more interesting reads and solutions in the future. Happy coding!

Question: Given a Python list of hexadecimal strings such as ['ff', 'ef', '0f', '0a', '93']. How to convert it to a list of integers in Python such as [255, 239, 15, 10, 147]?

Easiest Answer

The easiest way to convert a list of hex strings to a list of integers in Python is the list comprehension statement [int(x, 16) for x in my_list] that applies the built-in function int() to convert each hex string to an integer using the hexadecimal base 16, and repeats this for each hex string x in the original list.

Here’s a minimal example:

my_list = ['ff', 'ef', '0f', '0a', '93']

my_ints = [int(x, 16) for x in my_list] print(my_ints)

# [255, 239, 15, 10, 147]

The list comprehension statement applies the expression int(x, 16) to each element x in the list my_list and puts the result of this expression in the newly-created list.

The int(x, 16) expression converts a hex string to an integer using the hexadecimal base argument 16. A semantically identical way to write this would be int(x, base=16).

In fact, there are many more ways to convert a hex string to an integer—each of them could be used in the expression part of the list comprehension statement.

However, I’ll show you one completely different approach to solving this problem without listing each and every combination of possible solutions.

For Loop with List Append

You can create an empty list and add one hex integer at a time in the loop body after converting it from the hex string x using the eval('0x' + x) function call. This first creates a hexadecimal string with '0x' prefix using string concatenation and then lets Python evaluate the string as if it was real code and not a string.

Here’s an example:

my_list = ['ff', 'ef', '0f', '0a', '93'] my_ints = []

for x in my_list: my_ints.append(eval('0x' + x)) print(my_ints)

# [255, 239, 15, 10, 147]

You use the fact that Python automatically converts a hex value of the form 0xff to an integer 255:

>>> 0xff

255

>>> 0xfe

254

>>> 0x0f

15

You may want to check out my in-depth guide on this important function for our solution:

Recommended Tutorial: Python eval()