This document summarizes key topics from a Python lecture on strings, including membership operators, string constants, Boolean string methods, and string methods. It discusses using the 'in' and 'not in' operators to check if a character is in a string. It also covers built-in string constants for lowercase, uppercase, digits, and more. Boolean string methods like isalpha(), islower(), and isupper() are explained. Finally, common string methods such as capitalize(), count(), find(), and replace() are overviewed.

2. Python
Lecture 4
Problem Set 4: String

3. Topic
• Membership Operator
• String Constants
• String Boolean Methods
• String Methods
• Problem Set 4: String (11)

4. Membership Operator
• in
• not in

5. Character input/ output and ASCII value
char = input()
print(char)
char = input()
print(char)
print(ord(char))
char = 'A'
print(ord(char))
char = input()
print(char, " = ", ord(char))

6. Character input/ output and ASCII value 2
for c in range(33,48):
print(chr(c), end = ' ')
print()
for c in range(48,58):
print(chr(c), end = ' ')
print()
for c in range(58,65):
print(chr(c), end = ' ')
print()
for c in range(65,91):
print(chr(c), end = ' ')
print()
for c in range(91,97):
print(chr(c), end = ' ')
print()
for c in range(97,123):
print(chr(c), end = ' ')
print()

7. ASCII
c = '0'
print("Char ASCII")
while c<='9':
print(f'{c:4} {ord(c):3}')
c = chr(ord(c) + 1)

8. ASCII
c = 'A'
print("Char ASCII")
while c<='Z':
print(f'{c:4} {ord(c):3}')
c = chr( ord(c) + 1)
c = 'a'
print("Char ASCII")
while c<='z':
print(f'{c:4} {ord(c):3}')
c = chr( ord(c) + 1)

9. String constants
• string.ascii_lowercase
• abcdefghijklmnopqrstuvwxyz
• string.ascii_uppercase
• ABCDEFGHIJKLMNOPQRSTUVWXYZ
• string.ascii_letters
• ascii_lowercase, ascii_uppercase

10. String constants
• string.digits
• 0123456789
• string.hexdigits
• 0123456789abcdefABCDEF
• string.octdigits
• 01234567

11. String constants
• string.punctuation
• ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ ] ^ _ ` { | } ~
• string.whitespace
• space, tab, linefeed, return, formfeed, vertical tab
• string.printable
• String of ASCII characters which are considered printable. This is a
combination of digits, ascii_letters, punctuation, and whitespace.

12. String constants
import string
for c in string.ascii_lowercase:
print(c,end=' ')

13. String constants 1
import string
char = 'A'
if char in string.ascii_letters:
print("Alphabet")
else:
print("Not")
char = '5'
if char in string.digits:
print("Digit")
else:
print("Not")
char = '?'
if char not in string.ascii_letters and char
not in string.digits :
print("Special")
else:
print("Not")

14. String constants 2
char = 'A'
if char in string.ascii_uppercase:
print("Upper Case")
else:
print("Not")
char = 'a'
if char in string.ascii_lowercase:
print("Lower Case")
else:
print("Not")
vowel = 'aeiouAEIOU'
char = 'A'
if char in vowel:
print("Vowel")
else:
print("Not")
char = 'R'
if char not in vowel:
print("Consonant")
else:
print("Not")

15. String Matching
str1 = "EWU"
str2 = "EWU"
if str1 == str2:
print("Matched")
else:
print("Not Matched")
str1 = "EWU"
str2 = "ewu"
if str1 == str2:
print("Matched")
else:
print("Not Matched")

16. String Reverse
str = "EWU"
print(str[::-1])
str1 = "EWU"
str2 = str1[::-1]
print(str2)

17. String Methods
• https://docs.python.org/3.6/library/stdtypes.html#string-methods
• str.capitalize()
• Return a copy of the string with its first character capitalized and the rest lowercased.
• str.count(sub[, start[, end]])
• Return the number of non-overlapping occurrences of substring sub in the range
[start, end]. Optional arguments start and end are interpreted as in slice notation.
• str.find(sub[, start[, end]])
• Return the lowest index in the string where substring sub is found within the slice
s[start:end]. Optional arguments start and end are interpreted as in slice notation.
Return -1 if sub is not found.
• str.replace(old, new[, count])

18. String Methods
• string.upper()
• string.lower()

19. String Boolean Methods
• str.isalnum()
• String consists of only alphanumeric characters (no symbols)
• str.isalpha()
• String consists of only alphabetic characters (no symbols)
• str.isdecimal()
• String consists of only decimal characters
• str.isspace()
• String consists of only whitespace characters

20. String Boolean Methods
• str.islower()
• String’s alphabetic characters are all lower case
• str.isupper()
• String’s alphabetic characters are all upper case
• string.istitle()
• String is in title case

21. String Function
• ord(char)
• chr(num)

22. Problem Set 4: String (11)
• Character input/ output and ASCII value.
• Check is a Character Alphabet/ Digit/ Special Character.
• Check is an Alphabet Vowel or Consonant.
• Check is an Alphabet Upper or Lower Case.
• Input/ Output String and count number of character (String Length count).
• Count Upper and Lower Case in a sentence.
• Change Case (Upper Case to Lower Case).
• String Matching
• String Reverse
• Palindrome
• Word Sorting (Dictionary)

23. Any Question?

24. Prepared by
Mun Al Mamun
President
East West University Robotics Club
munewu@gmail.com
T h i s s l i d e i s p r o v i d e a s a c o u r s e
m a t e r i a l i n t h e w o r k s h o p
“ W o r k s h o p O n P y t h o n P r o g r a m m i n g ”
O r g a n i z e d b y
E a s t W e s t U n i v e r s i t y R o b o t i c s C l u b