A string is a sequence of characters that represent textual data.
String are created by enclosing a sequence of characters within quotes, either single quotation marks ‘’ , or double quotation marks ” ”.
Syntex:
a =“String value” #is a same as ‘String value’
Example,
print(“hello”) #output : hello
print(‘hello’) #output: hello , is the same as print(“hello”)
#create a string
string = “my first string value”
print(string) #output: my first string value
We can assign a multiline string to a variable using three quotes. Syntax,
A = “””line 1
Line 2
line 3”””
a = ‘“this my multiple lines,
string ”’
print(a) “”” output: this my multiple lines,
string”””
iv - Check existing variable in string:
In python, we can check if a certain character is existing in a string by using keyword in.
Syntax:
if value in String:
do
Example,
x=”hello!! you are in resume of python ”# makes a sentence an object by named x
a= “resume” # make a word an object by named a
if a in x: #condition to excute
print(‘yes its present’) # to check
else: # incase insatisfaction of condition
print( ‘no there’s not’) #what you have to do
Also, we can check if character is not present by using keyword not in. Example,
x=”hello!! you are checking if that is actually working ”
a= “resume”
if a in not x:
print(‘yes its present’)
else:
print( ‘no there’s not’)
Result:
v - Slicing in string:
In Python, slicing is method that returns a range of characters.
Syntax:
sentence[ start_index : end_index, step]
specify the start index and the end index, and the step parameter is optional, by defaults step is equal to 1. Example,
a = “hello!! My name is hatim ”
print( a[0:5]) #output: hello!
vi - Modify a string:
In python, we can modify a string after creating it by recreating it again. Example,
x = “hatim”
print(x) #output: hatim
x= “hat” # modify the value of x
print(x) #output: hat
vii - upper() method:
The upper() method is a function that converts a string to uppercase and returns it. Example,
a = “hello !! my name is hatim”
print(a.upper()) #output : HELLO!! MY NAME IS HATIM
viii - lower() method:
The lower() method is function that converts a string to lowercase and returns it. Example,
a = “HELLO!! MY NAME IS HATIM”
print(a.lower()) #output : hello!! My name is hatim
ix - strip() method to remove whitespace:
The strip() method is function that removes any leading or trailing whitespace characters in string. Example,
a= “hello!! My name is hatim ”
print(a.strip()) #output : hello!! my name is hatim
x - Capitalize() method:
The capitalize() method is function that converts a string to Capitalize ad returns it. Example
a = “hello!! my name is hatim ”
print(a) #output: Hello!! my name is hatim
xi - Replace() method to replace in string:
The replace() method is function that substituted character in string with another string. Example,
a = “hello !! my name is hatim”
print(a.replace(“h”,”j”))#output : jello!! my name is jatim
xii - Split() method to split a string:
The split() method is function that generates a list of substrings by using the specified separator to split the original string into individual items within the list. Example,
a = “hello! my name is hatim, ”
print(a.split(“!”)) #output : [“hello”, “my name is hatim”]
xiii - String concatenation:
In python, concatenation, combination and join two or multiples strings together can be done by using the operator +. Example,
a=”hatim”
b=”benjebara”
print(a+’’ ”+b) #output : hatim benjebara
ps: + is also mathematic operateur, don’t mix string with float or int.
xiv - Format() method to string format:
The format () method is function that print a combination of a string and numerical data. Example,
age = “35”
work = “data analyst”
number_phone = “00212674495530”
txt = “My name is hatim, and I am {} and I have {} years ago and this my number phone {}”
print(txt.format(work, age, number_phone))
Result:
My name is hatim, and I am data analyst and I have 35 years ago and this my number phone 00212674495530
Also, we can indice a position of variables by using a number of index. Example,
print(“my number phone is {2}, I am {0} and I have {1}”.format(work, age, number_phone))
Result:
my number phone is 00212674495530, I am data analyst and I have 35
xv - Escape character:
In Python, some character is not allow to use inside the string. However, we can print them by using an espace character (a backslash).
List of not normal characters:
• \’ : single Quote
• \ : Backslash
• \n: newline
• \r : Carriage return
• \t : tab
• \b : backspace
• \f : form feed
• \ooo : octal value
• \xhh : hex value
xvi - String methods:
List of methods available for string in python:
• captitalize(): Converts the first character to upper case.
• casefold() : Converts string into lower case.
• center() : Returns a centred string.
• count(): Returns the number of times a specified value occurs in a string
• encode(): Returns an encoded version of the string
• endswith() : Returns true if the string ends with the specified value
• expandtabs(): Sets the tab size of the string
• find() : Searches the string for a specified value and returns the position of where it was found
• format(): Formats specified values in a string.
• format_map(): Formats specified values in string.
• index(): Searches the string for a specified value and returns the position of where it was found.
• isalnum(): Returns True if all characters in the string are alphanumeric
• isalpha(): Return true if all characters in the string are in the alphabet
• isdecimal(): Returns true if all characters in the string are decimals
• isdigit(): Returns true If the string is an identifier
• isidentifier(): Returns true if the string is an identifier
• islower(): Returns true if all characters in the string are lower case
• isnumeric(): Returns true if all characters in the string are numeric
• isprintable(): Return true if all characters in the string are printable
• isspace(): Return true if all characters in the string are whitespaces
• istitle(): Return true if the string follows the rules of a title
• isupper(): Return true if all characters in the string are upper case
• join(): Join the elements of an iterable to the end of the string
• ljust(): Return a left justified version of the string
• lower(): Converts a string into lower case
• istrip() : Returns a left trim version if the string
• maketrans() : Returns a translation table to be used in translations
• partition(): Returns a tuple where the string is parted into three parts
• replace(): Returns a string where a specified value is replaced with a specified value
• rfind(): Searches the string for a specified value and returns the last position of where it was found
• rindex(): Searches the string for a specified value and returns the last position of where it was found
• rjust(): Returns a right justified version of the string
• rpartition(): Returns a right justified version of the string
• rsplit() : Return the right trim version of the string
• split() : Splits the string at the specified separator, and returns a list
• splitlines(): Splits the string at line breaks and returns a list
• startswith(): Returns true if the string with the specified value
• strip(): Returns a trimmed version of the string
• swapcase(): Swaps cases, lower case becomes upper case and vice versa
• title(): Converts the first character of each word to upper case
• translate(): Returns a translated string
• upper() : Converts a string into upper case
• zfill(): Fills the string with a specified number of 0 values at the beginning