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Python Day-String functions logic using loops,Task

Patricia Arquette

Release： 2024-12-14 18:34:11

Original

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Python Day-String functions logic using loops,Task

1) find(): Searches the string for a specified value and returns the position of where it was found.

txt = "I love many fruits, apple is my favorite fruit"
key = 'fruit'
l = len(key)
start = 0 
end = l
while end<=len(txt):
    if txt[start:end] == key:
        print('Contains', key)
        print(start, end-1)
        break
    start+=1
    end+=1
else:
    print('Not Contains')

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Output:

Contains fruit
12 16

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2) startswith(): Returns true if the string starts with the specified value

Example:1

#starts with: 
txt = "Python is my favourite language"
key = 'Python'
l = len(key)
start = 0 
end = l
while end<len(txt):
    if txt[start:end] == key:
        if start == 0:
            print("Starts with",key)
        break
    start+=1
    end+=1
else:
    print('Not Contains')

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Output:

Starts with Python

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Example:2

txt = "Apples are good, apple is my favorite fruit"
key = 'Apple'
#starts with
l = len(key) #5
if txt[0:l] == key:
    print('Starts with',key)

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Output:

Starts with Apple

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3) endswith(): Returns true if the string ends with the specified value.
Example:1

txt = "Apples are good, apple is my favorite fruit"
key = 'fruit'
#starts with
l = len(key) #5
if txt[-len(key):] == key:
    print('Ends with',key)

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Output:

Ends with fruit

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Example:2

txt = "Python is my favourite language"
key = 'language'
l = len(key)
start = 0 
end = l
while end<=len(txt):
    if txt[start:end] == key:
        if end==len(txt):
            print("Ends with",key)
        break
    start+=1
    end+=1
else:
    print('Not ending with language')

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Output:

Ends with language

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4) isalpha(): Returns True if all characters in the string are in the alphabet.

Method:1

word = 'abcdEFGH'
for letter in word:
    if letter>='a' and letter<='z' or letter>='A' and letter<='Z':
        continue
    else:
        print('not all are alphabets')
        break
else:
    print('All are alphabets')

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Method:2

alpha = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
word = 'abcdEFGH'
for letter in word:
    if letter not in alpha:
        print('Not all are alphabets')
        break
else:
    print('All are alphabets')

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Output:

All are alphabets

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5) isalnum(): Returns True if all characters in the string are alphanumeric.

#isalnum
alpha = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
word = 'abcd1234'
for letter in word:
    if letter not in alpha:
        print('Not all are alphabets and numbers')
        break
else:
    print('All are alphabets and numbers')

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Output:

All are alphabets and numbers

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6) islower(): Returns True if all characters in the string are lower case.

#islower
alpha = 'abcdefghijklmnopqrstuvwxyz'
word = 'lakshmipritha'
for letter in word:
    if letter not in alpha:
        print('Not all are lower alphabets')
        break
else:
    print('All are lower alphabets')

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Output:

All are lower alphabets

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7) isupper(): Returns True if all characters in the string are upper case.

#isupper
alpha = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
word = 'GURU'
for letter in word:
    if letter not in alpha:
        print('Not all are UPPERCASE alphabets')
        break
else:
    print('All are UPPERCASE alphabets')

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Output:

All are UPPERCASE alphabets

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8) isspace(): Returns True if all characters in the string are whitespaces.

#isspace

word = '        '
for letter in word:
    if letter != ' ':
        print("not all are spaces")
        break
else:
    print('All are spaces')

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Output:

All are spaces

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Tasks:
1) lower(): Converts a string into lower case.

txt = "PYTHON IS MY FAVOURITE LANGUAGE"
for letter in txt:
    if letter>='A' and letter<='Z':
        letter = ord(letter)+32
        letter = chr(letter)
    print(letter,end='')

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Output:

python is my favourite language

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2) upper(): Converts a string into upper case.

txt = "python is my favourite language"
for letter in txt:
    if letter>='a' and letter<='z':
        letter = ord(letter)-32
        letter = chr(letter)
    print(letter,end='')

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Output:

PYTHON IS MY FAVOURITE LANGUAGE

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