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Python - String Function

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• Python - String Function
  • Converting Data Type
    • join(iterable): list to string
    • split(separator, maxsplit): string to list
    • rsplit(separator, maxsplit)
    • splitlines(keeplinebreaks)
  • Format
    • format(value)
  • Converting Case
    • capitalize()
    • istitle()
    • title()
    • isupper()
    • upper()
    • islower()
    • lower()
    • casefold()
    • swapcase()
  • Checking Content
    • startswith(value, start, end)
    • endswith(value, start, end)
    • isspace()
    • isalnum()
    • isalpha()
    • isnumeric()
    • isdigit()
    • isdecimal()
    • isidentifier()
    • isprintable()
  • Searching
    • count(value, start, end)
    • find(value, start, end)
    • rfind(value, start, end)
    • index(value, start, end)
    • rindex(value, start, end)
    • partition(value)
    • rpartition(value)
  • Replace
    • replace(oldvalue, newvalue, count)
    • translate(table)
    • str.maketrans(x, y, z)
  • Trimming
    • strip(characters)
    • lstrip(characters)
    • rstrip(characters)
  • Padding
    • center(length, character)
    • ljust(length, character)
    • rjust(length, character)
    • zfill(len)
    • expandtabs(tabsize)

---

Converting Data Type

join(iterable): list to string

• takes all items in an iterable and joins them into one string.

• A string must be specified as the separator.

• Parameter
  • iterable: Required. Any iterable object where all the returned values are strings

print("\n--------string.join(iterable)--------\n")

xSeparator = ","

xStr = "John"
result = xSeparator.join(xStr)
print(result) # J,o,h,n

# set is not iterable, so get an error.

xSet = {"1","2","3"}
result = xSeparator.join(xSet)
print(result) # 3,1,2 由于 set 是无序的,所以每次输出是

xList = ["1","2","3"]
result = xSeparator.join(xList)
print(result) # 1,2,3

xDict = {"name": "John", "country": "Norway"}
xSeparator = "TT"
result = xSeparator.join(xDict)
print(result) # nameTTcountry

---

split(separator, maxsplit): string to list

• splits a string into a list.

print("\n--------string.split(separator, maxsplit)--------\n")

# Parameter     Description
# separator     Optional. Specifies the separator to use when splitting the string. By default any whitespace is a separator
# maxsplit      Optional. Specifies how many splits to do. Default value is -1, which is "all occurrences" When maxsplit is specified, the list will contain the specified number of elements plus one.

txt = "welcome to the jungle"
xList = txt.split()
print(xList) # ['welcome', 'to', 'the', 'jungle']

txt = "hello, my name is Peter, I am 26 years old"
xList = txt.split(", ")
print(xList) # ['hello', 'my name is Peter', 'I am 26 years old']

txt = "apple#banana#cherry#orange"
xList = txt.split("#")
print(xList) # ['apple', 'banana', 'cherry', 'orange']

txt = "apple#banana#cherry#orange"

# setting the maxsplit parameter to 1, will return a list with 2 elements!

x = txt.split("#", -1)
print(x) # ['apple', 'banana', 'cherry', 'orange']
x = txt.split("#", 0)
print(x) # ['apple#banana#cherry#orange']
x = txt.split("#", 1)
print(x) # ['apple', 'banana#cherry#orange']
x = txt.split("#", 2)
print(x) # ['apple', 'banana', 'cherry#orange']
x = txt.split("#", 3)
print(x) # ['apple', 'banana', 'cherry', 'orange']
x = txt.split("#", 4)
print(x) # ['apple', 'banana', 'cherry', 'orange']

---

rsplit(separator, maxsplit)

• splits a string into a list, starting from the right.

print("\n--------string.rsplit(separator, maxsplit)--------\n")

# Parameter     Description
# separator     Optional. Specifies the separator to use when splitting the string. By default any whitespace is a separator
# maxsplit      Optional. Specifies how many splits to do. Default value is -1, which is "all occurrences" When maxsplit is specified, the list will contain the specified number of elements plus one.

txt = "welcome to the jungle"
xList = txt.rsplit()
print(xList) # ['welcome', 'to', 'the', 'jungle']

txt = "hello, my name is Peter, I am 26 years old"
xList = txt.rsplit(", ")
print(xList) # ['hello', 'my name is Peter', 'I am 26 years old']

# txt = "apple#banana#cherry#orange"
# xList = txt.split("#")
# print(xList) # ['apple', 'banana', 'cherry', 'orange']

txt = "apple#banana#cherry#orange"

# setting the maxsplit parameter to 1, will return a list with 2 elements!

x = txt.split("#", -1)
print(x) # ['apple', 'banana', 'cherry', 'orange']
x = txt.rsplit("#", 0)
print(x) # ['apple#banana#cherry#orange']
x = txt.rsplit("#", 1)
print(x) # ['apple#banana#cherry', 'orange']
x = txt.rsplit("#", 2)
print(x) # ['apple#banana', 'cherry', 'orange']
x = txt.rsplit("#", 3)
print(x) # ['apple', 'banana', 'cherry', 'orange']
x = txt.rsplit("#", 4)
print(x) # ['apple', 'banana', 'cherry', 'orange']

---

splitlines(keeplinebreaks)

• splits a string into a list. The splitting is done at line breaks.

print("\n--------string.splitlines(keeplinebreaks)--------\n")

# Parameter         Description
# keeplinebreaks    Optional. Specifies if the line breaks should be included (True), or not (False). Default value is False

print("Thank you for the music\nWelcome to the jungle".splitlines()) # ['Thank you for the music', 'Welcome to the jungle']
print("Thank you for the music\nWelcome to the jungle".splitlines(True)) # ['Thank you for the music\n', 'Welcome to the jungle']

---

Format

format(value)

• formats the specified value(s) and insert them inside the string’s placeholder.

• The placeholder is defined using curly brackets: {}.

  • returns the formatted string.

1. The placeholders can be identified using named indexes {price}
2. numbered indexes {0},
3. or even empty placeholders {}.

print("\n--------string.format(value1, value2...)--------\n")

# named indexes:
txt1 = "My name is {fname}, I'm {age}".format(
    age=36, fname="John")
print(txt1)  # My name is John, I'm 36

# numbered indexes:
txt2 = "My name is {1}, I'm {0}".format(36, "John")
print(txt2)  # My name is John, I'm 36

# empty placeholders:
txt3 = "My name is {}, I'm {}".format("John", 36)
print(txt3)  # My name is John, I'm 36

• Formatting Types

# :< Left aligns the result (within the available space)
print("We have {:<8} chickens.".format(49))  # We have 49       chickens.

# :> Right aligns the result (within the available space)
print("We have {:>8} chickens.".format(49))  # We have       49 chickens.

# :^ Center aligns the result (within the available space)
print("We have {:^8} chickens.".format(49)) # We have    49    chickens.

# := Places the sign to the left most position
print("The temperature is {:=8} degrees celsius.".format(49))
# The temperature is       49 degrees celsius.

# :+ Use a plus sign to indicate if the result is positive or negative
txt = "The temperature is between {:+} and {:+} degrees celsius."
print(txt.format(-3, 7))
# The temperature is between -3 and +7 degrees celsius.

# :- Use a minus sign for negative values only
txt = "The temperature is between {:-} and {:-} degrees celsius."
print(txt.format(-3, 7))
# The temperature is between -3 and 7 degrees celsius.

# : Use a space to insert an extra space before positive numbers (and a minus sign before negative numbers)
txt = "The temperature is between {:-} and {:} degrees celsius."
print(txt.format(-3, 7))
# The temperature is between -3 and 7 degrees celsius.

# :, Use a comma as a thousand separator
txt = "The universe is {:,} years old."
print(txt.format(13800000000))
# The universe is 13,800,000,000 years old.

# :_ Use a underscore as a thousand separator
txt = "The universe is {:_} years old."
print(txt.format(13800000000))
# The universe is 13_800_000_000 years old.

# :b Binary format
txt = "The binary version of {0} is {0:b}"
print(txt.format(5))  # The binary version of 5 is 101

# :c Converts the value into the corresponding unicode character
# No sample

# :d Decimal format
txt = "We have {:d} chickens."
print(txt.format(0b101))  # We have 5 chickens.

# :e convert a number into scientific number format (with a lower-case e):
txt = "We have {:e} chickens."
print(txt.format(5))  # We have 5.000000e+00 chickens.

# :E Scientific format, with an upper case E
txt = "We have {:E} chickens."
print(txt.format(5))    # We have 5.000000E+00 chickens.

# :f Fix point number format
# default with 6 decimals
print("The price is {:f} dollars.".format(45))
# The price is 45.000000 dollars.

print("The price is {:.2f} dollars.".format(45))
# The price is 45.00 dollars.

# :F Fix point number format, in uppercase format (show inf and nan as INF and NAN)
x = float('inf')
txt = "The price is {:F} dollars."
print(txt.format(x)) # The price is INF dollars.

txt = "The price is {:f} dollars."
print(txt.format(x)) # The price is inf dollars.

# :g General format
# no sample

# :G General format (using a upper case E for scientific notations)
# no sample

# :o Octal format
txt = "The octal version of {0} is {0:o}"
print(txt.format(10)) # The octal version of 10 is 12

# :x Hex format, lower case
txt = "The Hexadecimal version of {0} is {0:x}"
print(txt.format(255))  # The Hexadecimal version of 255 is ff

# :X Hex format, upper case
txt = "The Hexadecimal version of {0} is {0:X}"
print(txt.format(255))  # The Hexadecimal version of 255 is FF

# :n Number format
# no sampple

# :% Percentage format
txt = "You scored {:%}"
print(txt.format(0.25))  # You scored 25.000000%

txt = "You scored {:.0%}"
print(txt.format(0.25)) # You scored 25%

---

Converting Case

capitalize()

• returns a string where the first character is upper case, and the rest is lower case.

print("\n--------string.capitalize()--------\n")

print("HELLO WORLD", ":", "HELLO WORLD".capitalize())   # Hello world
print("hello world", ":", "hello world".capitalize())   # Hello world
print("straße", ":", "straße".capitalize())  # Straße

---

istitle()

• returns True if all words in a text start with a upper case letter, AND the rest of the word are lower case letters, otherwise False.

• Symbols and numbers are ignored.

print("\n--------string.istitle()--------\n")

print("HELLO WORLD".istitle()) # False
print("hello world".istitle()) # False
print("Hello world".istitle()) # False
print("Hello World".istitle()) # True
print("123 Hello World".istitle()) # True
print("Hello World %'!?".istitle()) # True

---

title()

• returns a string where the first character in every word is upper case. Like a header, or a title.
• If the word contains a number or a symbol, the first letter after that will be converted to upper case.

print("\n--------string.title()--------\n")

print("Welcome to my world".title()) # Welcome To My World
print("Welcome to my 2nd world".title()) # Welcome To My 2Nd World
print("hello b2b2b2 and 3g3g3g".title()) # Hello B2B2B2 And 3G3G3G

---

isupper()

• returns True if all the characters are in upper case, otherwise False.

• Numbers, symbols and spaces are not checked, only alphabet characters.

print("\n--------string.isupper()--------\n")

print("hello world".isupper()) # False
print("Hello world".isupper()) # False
print("Hello World".isupper()) # False
print("HELLO WORLD".isupper()) # True
print("HELLO WORLD 123".isupper()) # True
print("HELLO WORLD %'!?".isupper()) # True

---

upper()

• returns a string where all characters are in upper case.
• Symbols and Numbers are ignored.

print("\n--------string.upper()--------\n")

print("Hello my friends".upper()) # HELLO MY FRIENDS
print("Hello World! (123)".upper()) # HELLO WORLD! (123)

---

islower()

• returns True if all the characters are in lower case, otherwise False.
• Numbers, symbols and spaces are not checked, only alphabet characters.

print("\n--------string.islower()--------\n")

print("Hello world!".islower()) # False
print("hello 123".islower()) # True
print("mynameisPeter".islower()) # False

---

lower()

• returns a string where all characters are lower case.

print("\n--------string.lower()--------\n")

print("HELLO WORLD".lower()) # hello world
print("hello world".lower()) # hello world
print("Hello World".lower()) # hello world
print("123 Hello World".lower()) # 123 hello world
print("Hello World %'!?".lower()) # hello world %'!?

print("Straße", ":", "Straße".lower())  # straße

---

casefold()

• Converts string into lower case

print("\n--------string.casefold()--------\n")

print("HELLO WORLD", ":", "HELLO WORLD".casefold())   # Hello world
print("hello world", ":", "hello world".casefold())   # Hello world
print("Straße", ":", "Straße".casefold())  # strasse

---

swapcase()

• returns a string where all the upper case letters are lower case and vice versa.

print("\n--------string.swapcase()--------\n")

print("Hello My Name Is PETER".swapcase()) # hELLO mY nAME iS peter

---

Checking Content

startswith(value, start, end)

• returns True if the string starts with the specified value, otherwise False.

print("\n--------string.startswith(value, start, end)--------\n")

# Parameter     Description
# value         Required. The value to check if the string starts with
# start         Optional. An Integer specifying at which position to start the search
# end           Optional. An Integer specifying at which position to end the search

print("Hello, welcome to my world.".startswith("Hello")) # True
print("Hello, welcome to my world.".startswith("wel", 7, 20)) # True

---

endswith(value, start, end)

• returns True if the string ends with the specified value, otherwise False.

print("\n--------string.endswith(value, start, end)--------\n")
# endswith(value, start, end)
# Parameter     Description
# value         Required. The value to check if the string ends with
# start         Optional. An Integer specifying at which position to start the search
# end           Optional. An Integer specifying at which position to end the search

print("banana", "banana".endswith("na")) # True

print("Hello World", ":", "Hello World".endswith("lo")) # False
print("Hello World", ":", "Hello World".endswith("World")) # True

print("Hello World", ":", "Hello World".endswith("llo")) # False
print("Hello World", ":", "Hello World".endswith("llo", 0, 5)) # True

---

isspace()

• returns True if all the characters in a string are whitespaces, otherwise False.

print("\n--------string.isspace()--------\n")

print("Helloworld!".isspace()) # False
print("Hello world!".isspace()) # False
print(" s ".isspace()) # False
print(" ".isspace()) # True

---

isalnum()

• True if all the characters are alphanumeric, meaning alphabet letter (a-z) and numbers (0-9).

print("\n--------string.isalnum()--------\n")

print("Company 12".isalnum()) # false
print("Company12%".isalnum()) # false
print("Company12".isalnum()) # true
print("Company".isalnum()) # true
print("1233".isalnum()) # true
print("!$@##%^&".isalnum()) # false

---

isalpha()

• True if all the characters are alphabet letters (a-z).

print("\n--------string.isalpha()--------\n")

print("Company 12".isalpha()) # false
print("Company12%".isalpha()) # false
print("1233".isalpha()) # false
print("Company".isalpha()) # true

---

isnumeric()

• returns True if all the characters are numeric (0-9), otherwise False.

• Exponents, like ² and ¾ are also considered to be numeric values.

• -1 and 1.5 are NOT considered numeric values,

  • because all the characters in the string must be numeric, and the - and the . are not.

print("\n--------string.isnumeric()--------\n")

print("Hello world!".isnumeric()) # False
print("\u0030".isnumeric()) # True, unicode for 0
print("\u00B2".isnumeric()) # True, unicode for &sup2
print("10km2".isnumeric()) # False
print("-1".isnumeric()) # False
print("1.5".isnumeric()) # False
print("1234".isnumeric()) # True

---

isdigit()

• Returns True if all the characters are digits, otherwise False.
• Exponents, like ², are also considered to be a digit.

print("\n--------string.isdigit()--------\n")

print("\u0030".isdigit()) # true, unicode for 0
print("\u00B2".isdigit()) # True, unicode for ²

print("Company 12".isdigit()) # False
print("Company".isdigit()) # False
print("1233".isdigit()) # True
print("12.33".isdigit()) # False

---

isdecimal()

• returns True if all the characters are decimals (0-9).

print("\n--------string.isdecimal()--------\n")

a = "\u0030" # unicode for 0
b = "\u0047" # unicode for G

print(a.isdecimal()) # True
print(b.isdecimal()) # False

print("Company".isdecimal()) # False
print("Company 12".isdecimal()) # false
print("Company12%".isdecimal()) # false
print("1233".isdecimal()) # True

---

isidentifier()

• Returns True if the string is a valid identifier, otherwise False.

• A string is considered a valid identifier if it only contains alphanumeric letters (a-z) and (0-9), or underscores (_).

• A valid identifier cannot start with a number, or contain any spaces.

• 字符串能否符合命名规范

print("\n--------string.isidentifier()--------\n")

print("MyFolder".isidentifier()) # True
print("Demo002".isidentifier()) # True
print("2bring".isidentifier()) # False
print("my demo".isidentifier()) # False

---

isprintable()

• returns True if all the characters are printable, otherwise False.

print("\n--------string.isprintable()--------\n")

print("Hello world!".isprintable()) # True
print("Hello! Are you #1?".isprintable()) # True
print("Hello!\nAre you #1?".isprintable()) # False

---

Searching

count(value, start, end)

• returns the number of times a specified value appears in the string.

print("\n--------string.count(value, start, end)--------\n")
# count(value, start, end)
# value Required. A String. The string to value to search for
# start Optional. An Integer. The position to start the search. Default is 0
# end Optional. An Integer. The position to end the search. Default is the end of the string

print("banana", "banana".count("a")) # 3
print("banana", "banana".count("aa")) # 0
print("banana", "banana".count("an")) # 2
print("Hello World", ":", "Hello World".count("o")) # 2
print("Hello World", ":", "Hello World".count("o", 5, 8)) # 1

---

find(value, start, end)

• finds the first occurrence of the specified value.
• returns -1 if the value is not found.

print("\n--------string.find(value, start, end)--------\n")
# Parameter Description
# value Required. The value to search for
# start Optional. Where to start the search. Default is 0
# end Optional. Where to end the search. Default is to the end of the string

print("Hello World", "Hello World".find("")) # 0
print("Hello World", "Hello World".find("a")) # -1
print("Hello World", "Hello World".find("W")) # 6
print("Hello World", "Hello World".find("l")) # 2
print("Hello World", "Hello World".find("ll")) # 2
print("Hello World", "Hello World".find("l", 2)) # 2, inclusive
print("Hello World", "Hello World".find("l", 3)) # 3
print("Hello World", "Hello World".find("l", 4)) # 9
print("Hello World", "Hello World".find("l", 4, 8)) # -1
print("Hello World", "Hello World".find("l", 4, 9)) # -1, exclusive
print("Hello World", "Hello World".find("l", 4, 10)) # 9

---

rfind(value, start, end)

• finds the last occurrence of the specified value.
• returns -1 if the value is not found.

print("\n--------string.rfind(value, start, end)--------\n")

# Parameter Description
# value     Required. The value to search for
# start     Optional. Where to start the search. Default is 0
# end       Optional. Where to end the search. Default is to the end of the string

print("Hello World", "Hello World".rfind("")) # 11, the length of string
print("Hello World", "Hello World".rfind("w")) # -1
print("Hello World", "Hello World".rfind("W")) # 6
print("Hello World", "Hello World".rfind("o")) # 7
print("Hello World", "Hello World".rfind("o", 7)) # 7 inclusive
print("Hello World", "Hello World".rfind("o", 8)) # -1
print("Hello World", "Hello World".rfind("o", 0, 7)) # 4 exclusive
print("Hello World", "Hello World".rfind("o", 0, 8)) # 7

---

index(value, start, end)

• finds the first occurrence of the specified value.
• raises an exception if the value is not found.
• is almost the same as the find() method, the only difference is that the find() method returns -1, if the value is not found.

print("\n--------string.index(value, start, end)--------\n")

# Parameter Description
# value     Required. The value to search for
# start     Optional. Where to start the search. Default is 0
# end       Optional. Where to end the search. Default is to the end of the string

print("Hello World", "Hello World".index("o")) # 4
print("Hello World", "Hello World".index("o", 5)) # 7
print("Hello World", "Hello World".index("o", 5, 8)) # 7

# print("Hello World", "Hello World".index("o", 5, 7)) # 7 ValueError: substring not found

# print("Hello World", "Hello World".index("o", 8)) # 7 ValueError: substring not found

txt = "Hello, welcome to my world."
print(txt.find("q")) # -1

# print(txt.index("q")) # ValueError: substring not found

---

rindex(value, start, end)

• finds the last occurrence of the specified value.
• raises an exception if the value is not found.

print("\n--------string.rindex(value, start, end)--------\n")

# Parameter Description
# value     Required. The value to search for
# start     Optional. Where to start the search. Default is 0
# end       Optional. Where to end the search. Default is to the end of the string

print("Hello World", "Hello World".rindex("")) # 11, the length of string
print("Hello World", "Hello World".rindex("o")) # 7
print("Hello World", "Hello World".rindex("o", 7)) # 7, inclusive

# print("Hello World", "Hello World".rindex("o", 8)) # ValueError: substring not found

print("Hello World", "Hello World".rindex("o", 0, 7)) # 4, exclusive

# print("Hello World", "Hello World".rindex("o", 0, 4)) # ValueError: substring not found

---

partition(value)

• searches for a specified string, and splits the string into a tuple containing three elements. note: searches for the first occurrence of the specified string

  • The first element contains the part before the specified string.
  • The second element contains the specified string.
  • The third element contains the part after the string.

• If the specified value is not found, the partition() method returns a tuple containing:

  • 1 - the whole string,
  • 2 - an empty string,
  • 3 - an empty string

print("\n--------string.partition(value)--------\n")
# Parameter     Description
# value         Required. The string to search for

txt = "I could eat bananas all day"

xFound = txt.partition("bananas")
print(xFound) # ('I could eat ', 'bananas', ' all day')

xNotFound = txt.partition("apples")
print(xNotFound) # ('I could eat bananas all day', '', '')

---

rpartition(value)

• searches for the last occurrence of a specified string, and splits the string into a tuple containing three elements.

  • The first element contains the part before the specified string.
  • The second element contains the specified string.
  • The third element contains the part after the string.

• If the specified value is not found, the rpartition() method returns a tuple containing:

  • 1. an empty string,
  • 1. an empty string,
  • 1. the whole string:

print("\n--------string.rpartition(value)--------\n")

# Parameter Description
# value     Required. The string to search for

txt = "I could eat bananas all day, bananas are my favorite fruit"
xFound = txt.rpartition("bananas")
print(xFound) # ('I could eat bananas all day, ', 'bananas', ' are my favorite fruit')
xFound = txt.rpartition("apples")
print(xFound) # ('', '', 'I could eat bananas all day, bananas are my favorite fruit')

---

Replace

replace(oldvalue, newvalue, count)

• replaces a specified phrase with another specified phrase.

• All occurrences of the specified phrase will be replaced, if nothing else is specified.

print("\n--------string.replace(oldvalue, newvalue, count)--------\n")

# Parameter Description
# oldvalue  Required. The string to search for
# newvalue  Required. The string to replace the old value with
# count     Optional. A number specifying how many occurrences of the old value you want to replace. Default is all occurrences

txt = "one one was a race horse, two two was one too."

xReplace = txt.replace("one", "three")
print(xReplace) # three three was a race horse, two two was three too.

xReplaceNotFound = txt.replace("xxx", "three")
print(xReplaceNotFound) # one one was a race horse, two two was one too.

xReplaceCount = txt.replace("one", "three", 2)
print(xReplaceCount) # three three was a race horse, two two was one too.

---

translate(table)

• returns a string where some specified characters are replaced with the character described in a dictionary, or in a mapping table.
• Use the maketrans() method to create a mapping table.
  • If a character is not specified in the dictionary/table, the character will not be replaced.
  • If you use a dictionary, you must use ascii codes instead of characters.

print("\n--------string.translate(table)--------\n")

# Parameter Description
# table     Required. Either a dictionary, or a mapping table describing how to perform the replace

xTable = str.maketrans("S", "P")
print("Hello Sam!".translate(xTable)) # Hello Pam!

xTable = str.maketrans("mSa", "eJo")
print("Hi Sam!".translate(xTable)) # Hi Joe!

# The third parameter in the mapping table describes characters that you want to remove from the string

mytable = str.maketrans("mSa", "eJo", "odnght")
print("Good night Sam!".translate(mytable)) # G i Joe!

# When using a dictionary instead of a mapping table, must use ascii codes instead of characters.

xDict = {109: 101, 83: 74, 97: 111, 111: None, 100: None, 110: None, 103: None, 104: None, 116: None}
print("Good night Sam!".translate(xDict)) # G i Joe!

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str.maketrans(x, y, z)

• returns a mapping table that can be used with the translate() method to replace specified characters.

• returns a dictionary describing each replacement, in unicode.

print("\n--------str.maketrans(x, y, z)--------\n")
# Parameter Description
# x         Required. If only one parameter is specified, this has to be a dictionary describing how to perform the replace. If two or more parameters are specified, this parameter has to be a string specifying the characters you want to replace.
# y         Optional. A string with the same length as parameter x. Each character in the first parameter will be replaced with the corresponding character in this string.
# z         Optional. A string describing which characters to remove from the original string.

txt = "Hi Sam!"
x = "mSa"
y = "eJo"

xtb = str.maketrans(x, y)
print(txt.translate(xtb)) # Hi Joe!

txt = "Good night Sam!"
x = "mSa"
y = "eJo"
z = "odnght"

xtb = str.maketrans(x, y, z)
print(xtb)
# {109: 101, 83: 74, 97: 111, 111: None, 100: None, 110: None, 103: None, 104: None, 116: None}
print(txt.translate(xtb)) # G i Joe!

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Trimming

strip(characters)

• removes any leading (spaces at the beginning) and trailing (spaces at the end) characters (space is the default leading character to remove)

print("\n--------string.strip(characters)--------\n")

# Parameter     Description
# characters    Optional. A set of characters to remove as leading/trailing characters

print(" banana ".strip()) # banana
print(",,,,,rrttgg.....banana....rrr".strip(",.grt")) # banana

---

lstrip(characters)

• removes any leading characters (space is the default leading character to remove)

print("\n--------string.lstrip(characters)--------\n")

# Parameter     Description
# characters    Optional. A set of characters to remove as leading characters

print(" HELLO WORLD ".lstrip(),"|") # HELLO WORLD |
print(",,,,,ssaaww.....HELLO".lstrip(",.asw"),"|") # HELLO |

---

rstrip(characters)

• removes any trailing characters (characters at the end a string), space is the default trailing character to remove.

print("\n--------string.rstrip(characters)--------\n")

# Parameter     Description
# characters    Optional. A set of characters to remove as trailing characters

print(" HELLO WORLD ".rstrip(),"|") # HELLO WORLD |
print(",,,,,ssaaww.....HELLO,,,,,ssaaww.....".rstrip(",.asw"),"|") # ,,,,,ssaaww.....HELLO |

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Padding

center(length, character)

• center align the string, using a specified character (space is default) as the fill character.

print("\n--------string.center(length, character)--------\n")
# length	Required. The length of the returned string
# character	Optional. The character to fill the missing space on each side. Default is " " (space)
print("banana", "|", "banana".center(20), "|")   # hello world
print("banana", "|", "banana".center(20, "*"), "|")   # *******banana*******
print("hello world", "|", "hello world".center(20), "|")   # hello world
print("hello world", "|", "hello world".center(
    20, "*"), "|")   # ****hello world*****

---

ljust(length, character)

• left align the string, using a specified character (space is default) as the fill character.

print("\n--------string.ljust(length, character)--------\n")
# Parameter     Description
# length        Required. The length of the returned string
# character     Optional. A character to fill the missing space (to the right of the string). Default is " " (space).

print("Hello".ljust(10),"|") # Hello |
print("Hello".ljust(10, "*"), "|")  # Hello***** |
# print("Hello".ljust(10,"**"),"|") # TypeError: The fill character must be exactly one character long

---

rjust(length, character)

• right align the string, using a specified character (space is default) as the fill character.

print("\n--------string.rjust(length, character)--------\n")

# Parameter Description
# length    Required. The length of the returned string
# character Optional. A character to fill the missing space (to the left of the string). Default is " " (space).

print("Hello".rjust(10), "|")  # Hello |
print("Hello".rjust(10, "*"), "|")  # *****Hello |
print("Hello world!".rjust(10,"*"),"|") # Hello world! |

# print("Hello".rjust(10,"**"),"|") # TypeError: The fill character must be exactly one character long

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zfill(len)

• adds zeros (0) at the beginning of the string, until it reaches the specified length.

• If the value of the len parameter is less than the length of the string, no filling is done.

print("\n--------string.zfill(len)--------\n")

# Parameter Description
# len       Required. A number specifying the desired length of the string

print("50".zfill(10)) # 0000000050
print("hello".zfill(10)) # 00000hello
print("welcome to the jungle".zfill(10)) # welcome to the jungle
print("10.000".zfill(10)) # 000010.000

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expandtabs(tabsize)

• sets the tab size to the specified number of whitespaces.

print("\n--------string.expandtabs(tabsize)--------\n")
# Parameter Description
# tabsize   Optional. A number specifying the tabsize. Default tabsize is 8

print("H\te\tl\tl\to")  # H e l l o
print("H\te\tl\tl\to".expandtabs())  # H       e       l       l       o
print("H\te\tl\tl\to".expandtabs(0))  # Hello
print("H\te\tl\tl\to".expandtabs(2))  # H e l l o
print("H\te\tl\tl\to".expandtabs(4))  # H   e   l   l   o

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