30-Days-Of-Python

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# Single line comment
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letter = 'P'                # A string could be a single character or a bunch of texts
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print(letter)               # P
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print(len(letter))          # 1
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greeting = 'Hello, World!'  # String could be  a single or double quote,"Hello, World!"
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print(greeting)             # Hello, World!
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print(len(greeting))        # 13
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sentence = "I hope you are enjoying 30 days of python challenge"
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print(sentence)
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# Multiline String
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multiline_string = '''I am a teacher and enjoy teaching.
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I didn't find anything as rewarding as empowering people.
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That is why I created 30 days of python.'''
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print(multiline_string)
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# Another way of doing the same thing
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multiline_string = """I am a teacher and enjoy teaching.
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I didn't find anything as rewarding as empowering people.
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That is why I created 30 days of python."""
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print(multiline_string)
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# String Concatenation
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first_name = 'Asabeneh'
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last_name = 'Yetayeh'
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space = ' '
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full_name = first_name  +  space + last_name
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print(full_name) # Asabeneh Yetayeh
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# Checking length of a string using len() builtin function
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print(len(first_name))  # 8
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print(len(last_name))   # 7
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print(len(first_name) > len(last_name)) # True
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print(len(full_name)) # 15
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#### Unpacking characters 
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language = 'Python'
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a,b,c,d,e,f = language # unpacking sequence characters into variables
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print(a) # P
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print(b) # y
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print(c) # t 
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print(d) # h
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print(e) # o
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print(f) # n
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# Accessing characters in strings by index
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language = 'Python'
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first_letter = language[0]
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print(first_letter) # P
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second_letter = language[1]
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print(second_letter) # y
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last_index = len(language) - 1
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last_letter = language[last_index]
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print(last_letter) # n
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# If we want to start from right end we can use negative indexing. -1 is the last index
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language = 'Python'
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last_letter = language[-1]
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print(last_letter) # n
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second_last = language[-2]
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print(second_last) # o
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# Slicing
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language = 'Python'
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first_three = language[0:3] # starts at zero index and up to 3 but not include 3
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last_three = language[3:6]
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print(last_three) # hon
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# Another way
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last_three = language[-3:]
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print(last_three)   # hon
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last_three = language[3:]
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print(last_three)   # hon
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# Skipping character while splitting Python strings
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language = 'Python'
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pto = language[0:6:2] # 
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print(pto) # pto
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# Escape sequence
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print('I hope every one enjoying the python challenge.\nDo you ?') # line break
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print('Days\tTopics\tExercises')
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print('Day 1\t3\t5')
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print('Day 2\t3\t5')
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print('Day 3\t3\t5')
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print('Day 4\t3\t5')
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print('This is a back slash  symbol (\\)') # To write a back slash
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print('In every programming language it starts with \"Hello, World!\"')
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## String Methods
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# capitalize(): Converts the first character the string to Capital Letter
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challenge = 'thirty days of python'
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print(challenge.capitalize()) # 'Thirty days of python'
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# count(): returns occurrences of substring in string, count(substring, start=.., end=..)
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challenge = 'thirty days of python'
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print(challenge.count('y')) # 3
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print(challenge.count('y', 7, 14)) # 1
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print(challenge.count('th')) # 2`
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# endswith(): Checks if a string ends with a specified ending
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challenge = 'thirty days of python'
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print(challenge.endswith('on'))   # True
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print(challenge.endswith('tion')) # False
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# expandtabs(): Replaces tab character with spaces, default tab size is 8. It takes tab size argument
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challenge = 'thirty\tdays\tof\tpython'
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print(challenge.expandtabs())   # 'thirty  days    of      python'
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print(challenge.expandtabs(10)) # 'thirty    days      of        python'
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# find(): Returns the index of first occurrence of substring
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challenge = 'thirty days of python'
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print(challenge.find('y'))  # 5
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print(challenge.find('th')) # 0
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# format()	formats string into nicer output    
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first_name = 'Asabeneh'
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last_name = 'Yetayeh'
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job = 'teacher'
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country = 'Finland'
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sentence = 'I am {} {}. I am a {}. I live in {}.'.format(first_name, last_name, job, country)
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print(sentence) # I am Asabeneh Yetayeh. I am a teacher. I live in Finland.
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radius = 10
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pi = 3.14
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area = pi # radius ## 2
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result = 'The area of circle with {} is {}'.format(str(radius), str(area))
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print(result) # The area of circle with 10 is 314.0
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# index(): Returns the index of substring
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challenge = 'thirty days of python'
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print(challenge.find('y'))  # 5
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print(challenge.find('th')) # 0
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# isalnum(): Checks alphanumeric character
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challenge = 'ThirtyDaysPython'
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print(challenge.isalnum()) # True
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challenge = '30DaysPython'
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print(challenge.isalnum()) # True
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challenge = 'thirty days of python'
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print(challenge.isalnum()) # False
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challenge = 'thirty days of python 2019'
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print(challenge.isalnum()) # False
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# isalpha(): Checks if all characters are alphabets
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challenge = 'thirty days of python'
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print(challenge.isalpha()) # True
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num = '123'
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print(num.isalpha())      # False
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# isdecimal(): Checks Decimal Characters
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challenge = 'thirty days of python'
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print(challenge.find('y'))  # 5
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print(challenge.find('th')) # 0
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# isdigit(): Checks Digit Characters
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challenge = 'Thirty'
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print(challenge.isdigit()) # False
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challenge = '30'
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print(challenge.digit())   # True
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# isdecimal():Checks decimal characters
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num = '10'
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print(num.isdecimal()) # True
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num = '10.5'
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print(num.isdecimal()) # False
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# isidentifier():Checks for valid identifier means it check if a string is a valid variable name
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challenge = '30DaysOfPython'
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print(challenge.isidentifier()) # False, because it starts with a number
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challenge = 'thirty_days_of_python'
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print(challenge.isidentifier()) # True
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# islower():Checks if all alphabets in a string are lowercase
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challenge = 'thirty days of python'
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print(challenge.islower()) # True
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challenge = 'Thirty days of python'
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print(challenge.islower()) # False
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# isupper(): returns if all characters are uppercase characters
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challenge = 'thirty days of python'
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print(challenge.isupper()) #  False
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challenge = 'THIRTY DAYS OF PYTHON'
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print(challenge.isupper()) # True
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# isnumeric():Checks numeric characters
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num = '10'
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print(num.isnumeric())      # True
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print('ten'.isnumeric())    # False
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# join(): Returns a concatenated string
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web_tech = ['HTML', 'CSS', 'JavaScript', 'React']
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result = '#, '.join(web_tech)
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print(result) # 'HTML# CSS# JavaScript# React'
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# strip(): Removes both leading and trailing characters
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challenge = ' thirty days of python '
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print(challenge.strip('y')) # 5
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# replace(): Replaces substring inside
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challenge = 'thirty days of python'
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print(challenge.replace('python', 'coding')) # 'thirty days of coding'
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# split():Splits String from Left
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challenge = 'thirty days of python'
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print(challenge.split()) # ['thirty', 'days', 'of', 'python']
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# title(): Returns a Title Cased String
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challenge = 'thirty days of python'
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print(challenge.title()) # Thirty Days Of Python
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# swapcase(): Checks if String Starts with the Specified String
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challenge = 'thirty days of python'
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print(challenge.swapcase())   # THIRTY DAYS OF PYTHON
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challenge = 'Thirty Days Of Python'
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print(challenge.swapcase())  # tHIRTY dAYS oF pYTHON
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# startswith(): Checks if String Starts with the Specified String
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challenge = 'thirty days of python'
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print(challenge.startswith('thirty')) # True
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challenge = '30 days of python'
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print(challenge.startswith('thirty')) # False