Day2-python Basic Knowledge: The method of the object

The following methods are common string methods that are summed up by Jingliyang in the work.

1. Count () method

Role: The number of characters specified in the statistics string.

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.count (' o ')  # If there are multiple characters in the string being counted, Only the position of the first character is counted print (a)

The result returned is: 3

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2. Center () method

Function: Returns a string that is centered on the specified width, and returns the string if the specified number of widths is less than the length of the string.

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = str.center (+, ' * ') print (a)

return The result is:

www.oldboyedu.com***************

Process has ended, exit code

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.center (10, ' * ') # The length of the width is less than the length of the string, showing only the string itself. Print (a)

return The result is:

Www.oldboyedu.com process has ended, exit code 0

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3. Find () method

Function: Finds the specified character, returns the subscript position of the character, and returns a value of 1 if no character is found

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.find (' l ') print (a)

The result returned is: 5

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.find (' F ') print (a)

The returned result is: -1

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4. Index () method

Function: Similar to find, the difference is that the index () method will error if no value is found, and find () will not error.

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.index (' l ') print (a)

The result returned is: 5

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.index (' x ')   # Find characters not in a string print (a)

The returned result is:

Traceback (most recent):   " c:/users/william/pycharmprojects/s4/day2/Basic command. PY "  in <module>    = Str.index ('x'not  found process has ended, exit code 1

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5, Str.isalnum ()

Function: Detects whether a string consists of only letters and numbers

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.isalnum ()  # because the string in STR is containing punctuation, So it returns a value of Falseprint (a)

The returned result is:

False process ended, exit code 0

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' jingliyang666 ' a = Str.isalnum ()  # because the strings in Str consist only of strings and numbers, So the return is Trueprint (a)

The returned result is:

True the process has ended, exit code 0

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6, Str.isalpha ()

Function: Determines if the string is not a letter, if yes returns true, otherwise false

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboy.com ' a = Str.isalpha ()   # Because the string contains punctuation marks, So the return result is Falseprint (a)

The returned result is:

False process ended, exit code 0

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' Jingliyang ' a = Str.isalpha ()   # Because the string contains only letters, return Trueprint (a)

The returned result is:

True the process has ended, exit code 0

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7, Str.isdigit ()

Function: Determines whether a string is made up of numbers, or returns True if it is, otherwise false

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' www.oldboyedu.com ' a = Str.isdigit () # because the str string contains punctuation marks, it returns Falseprint ( A

The returned result is:

False process ended, exit code 0

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' 666666 ' a = Str.isdigit ()  # The string is made up of numbers, so return Trueprint (a)

The returned result is:

True the process has ended, exit code 0

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8, Str.islower ()

Function: Determines whether all letters in a string are made up of lowercase letters.

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' Jingliyang ' a = Str.islower () print (a)

The returned result is:

False process ended, exit code 0

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' Jingliyang ' a = Str.islower ()  print (a)

The returned result is:

True the process has ended, exit code 0

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9, Str.isupper ()

Function: Determines whether all letters in the string are uppercase, uppercase returns TRUE, otherwise false

Example 1:

#!/usr/bin/env python# Author:william huangstr = ' Jingliyang ' a = Str.isupper () print (a)

The returned result is:

True the process has ended, exit code 0

Example 2:

#!/usr/bin/env python# Author:william huangstr = ' Jingliyang ' a = Str.isupper () print (a)

The returned result is:

False process ended, exit code 0

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9, Str.maketrans ()

Unknown

Special thanks to the "old boy" Jing-yang teacher took the time to explain their valuable patience.

Day2-python Basic Knowledge: The method of the object