Python Strings for Absolute Beginners

Python Strings are simple at first glance, but you can use them in many different ways. 
Today we’ll be looking at the string data type. A string is a sequence of characters. Anything inside quotes is considered a string in Python, and you can use single or double quotes around your strings like this: 

"Hello, World!"
'Hello, World!'

This property permits you to use quotations and apostrophes within a string:

'This is a string with "quotes," and it is fine.'
"It's fine to use apostrophes in a string."

Changing a String Case with Methods

It is relatively easy to change the case of the words in a string. See the code below, and attempt to determine the result:

name = "inye allison" 
print(name.title())

The result of the above code will be:

Inye Allison

The lowercase string “inye allison” is stored in the variable name in this example. The method title() was applied to the variable in the print() statement. A method is a function that belongs to an object. In this case, the title method belongs to the string class. The dot (.) after name in name.title() instructs Python to apply the title() method act to the variable name, which has a class type of String. A set of parentheses follows every method because methods often require additional information to do their job; this information is called parameters. The title() function does not need any parameter, so its parentheses are empty. “title()” displays each word in the title case, where each word begins with a capital letter; this helps your program recognize that input values Inye, INYE, and inye as the same name and depict all of them as Inye. Several other practical methods are available for handling string cases. For instance, you can transform a string to all uppercase or all lowercase alphabets like this:

name = "inye allison" 
print(name.upper())

print(name.lower())

The result will be:

INYE ALLISON
inye allison

The lower() method is beneficial for data storage; you often can’t trust the capitalization at the user input, so it is advisable to convert strings to lowercase before storing them. When retrieving the String, it can be transformed back to a more suitable case.

Python Strings Concatenating

It’s often helpful to be able to combine strings. For instance, you might want to store a first and a last name in separate variables or locations and then combine them whenever you need to show someone’s full name:

f_name = "inye"
l_name = "allison"
full_name = f_name + " " + l_name print(full_name)

print(full_name)

Python uses the plus sign (+) to merge strings. In the above example, we used “+” to make a full name by combining the first_name, a space, and a last_name , and we got this result:

inye allison

This manner of combining strings is called string concatenation. You can use string concatenation to form complete messages utilizing the data you’ve stored in a variable. Let’s look at an example: 

print("Hi, my name is " + full_name.title() + "!")

Here, the sentence is an introduction with my name, and the title() method is used to format the name correctly. This code produces an accessible but well-formatted introduction.

Hi, my name is Inye Allison.

You can compose a message with string concatenation and then store the message in a variable:

f_name = "inye"
l_name = "allison"
full_name = f_name + " " + l_name print(full_name)
msg = "Hi, my name is " + full_name.title() + "!"

print(msg)

Result:

Hi, my name is Inye Allison.

Tabs or Newlines in Python Strings

In Python programming, whitespace is any nonprintable character, such as spaces, tabs, and end-of-line characters. We can employ whitespace to manage your output, so it’s easier for users to read.

To add a tab to your String, use the character combination \t as shown below:

print("Python") 
print("\tPython")

Result:

Python
    Python

To add a new line to your String, use “\n” as shown below:

print("Languages:\nPython\nC\nJavaScript") 

Result:

Languages:
Python 
C 
JavaScript

A combination of tabs and newline “\n\t” can be used in a single string. The String makes Python move to a new line and start the following line with a tab. The next instance indicates how you can use a one-line string to generate four lines of results: 

print("Languages:\n\tPython\n\tC\n\tJavaScript") 

Result:

Languages:
   Python 
   C 
   JavaScript

Stripping Whitespace from Python Strings

Additional whitespace can make your programs need to be clarified. To programmers, the string ‘python’ and ‘python’ look the same. But to the interpreter program, they are two different strings. Python sees the additional space in the ‘python’ string and considers it meaningful unless you ask it to think otherwise. It’s essential to pay attention to whitespace because often, you’ll want to compare two strings to determine whether they are the same. For example, one crucial instance might involve checking people’s usernames when they login to a website. Extra whitespace can be confusing in much simpler situations as well. Fortunately, Python makes it easy to eliminate extraneous whitespace from data that people enter. Python can look for extra whitespace on a string’s right and left sides. To ensure that there is no whitespace at the right end of the String, we use the “rstrip()” method.

>>>language = 'python '
>>>language
'python'
>>>language.rstrip()
>>>language
'python'

The language variable in the above code initially contains an extra whitespace at the end of the String. But after the rstrip() method operates on the variable language, and the extra space is removed. However, the change is temporary. If you request the value of language once more, you will get the version with the extra whitespace. To permanently remove the whitespace from the String, you have to strip the String in language and store it back into the language variable like this:

>>> language = 'python '
>>> language = language.rstrip() 
>>> language 
'python'

Modifying a variable’s value and storing the new value back in the original variable is usually done in programming. This is how a variable’s value can change as a program is executed or in response to user input. You can also strip whitespace from the left side of a string with the lstrip() method or strip whitespace from both sides using strip():

>>>language = ' python ' 
>>> language.rstrip()
' python' 
>>> language.lstrip() 
>>> language 
'python '
>>>language.strip()
'python'

The code above starts with a value with a whitespace at the beginning and the end. We then remove the extra space from the right side using rstrip(), from the left side using lstrip(), and from both sides using strip(). Testing these stripping functions can help you become familiar with manipulating strings. In the real world, these stripping methods are primarily used to clean up user input before storing it in a program.

Tips to Avoid Syntax Errors when working with Strings 

One error that you might see with some regularity is a syntax error. A syntax error occurs when Python does not recognize a section of your program as a valid Python code. For instance, you’ll produce an error if you use an apostrophe within single quotes. You’ll get a syntax error, and this happens because Python interprets everything between the first single quote and the apostrophe as a string and then tries to understand the rest of the text as a Python expression, which generates errors. Here’s how to use single and dual quotes correctly:

msg = "One of Python's strengths is its diverse community." print(msg)

The apostrophe is inside the set of double quotes, so the Python interpreter has no problem reading the String correctly:

msg = 'One of Python's strengths is its diverse community.'
print(msg)

But, if you use single quotes, Python cannot identify where the String should terminate, and you’ll get the following output:

 File "string.py", line 1 
    message = 'One of Python's strengths is its diverse community.'
                            ^
SyntaxError: invalid syntax 

The output shows that the error occurs right after the second single quote. This syntax error means the interpreter doesn’t recognize part of the code as valid Python code. Errors can have various origins, and I’ll point out some common ones as they arise. You might see syntax errors often as you learn to write proper Python code. Syntax errors are also the least specific, making them challenging and frustrating to recognize and correct, so you need to pay adequate attention to details. Most times, your code editor’s syntax autocorrect feature will help you locate some syntax errors fast as you write your programs. 

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