Python Built-in String Methods/ Functions 1
Tags: programming, python, tutorial, codenewbie
Published: 2021-05-18 08:40:56

These are basic string functions() in python🐍.
>So, let the journey🏁 begin🚀....

## -  find()
The find() method finds the first occurrence of the specified value.
The find() method returns -1 if the value is not found.
```
input : string = 'python dev'
f = input.find(dev)
print (f)
Output : 7
w = input.find(z)
print(w)
Output : -1
```

## -  format()
The format() method formats the specified value(s) and insert them inside the string's placeholder. The placeholder is defined using curly brackets: {}
```
input : string = "For only {price:.2f} dollars!"
print(input.format(price = 49))
Output: 
For only 49.00 dollars!
```

## -  index()
This method returns the position at the first occurrence of the specified value.
```
fruits : string = ['apple', 'banana', 'cherry']
x = fruits.index("cherry")
Output: 2
```

## - isalnum()
isalnum() function in Python programming language checks whether all the characters in a given string is alphanumeric or not.
Alphanumeric:A character that is either a letter or a number
```
Input : string = 'abc123'
Output : True
Input : string = 'abc 123'
Output : False
```

## - isalpha()
The isalpha() methods returns true if all characters in the string are alphabets otherwise, It returns false.
```
Input : string = 'Developer'
Output : True
Input : string = 'The boy'
Output : False
Input : string = 'Devs0212'
Output : False
```           

## - isdecimal()
It is a function in Python that returns true if all characters in a string are decimal. If all characters are not decimal then it returns false.
```
input : string = '12345'
Output : True
input : string = '12e3y45'
Output : False
input : string = '12 45'
Output : False
```

## - isdigit()
isdigit() is a built-in method used for string handling. 
The isdigit() method returns true if all characters in the string are digits otherwise, It returns false
```
Input : string = '15460'
Output : True
Input : string = '154ban60'
Output : False
```
## - isidentifier()
The isidentifier() method 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.
```
input: 'Mydemo'
print(input.isidentifier())
Output: True
input: 'My demo'
print(input.isidentifier())
Output: False
```
## - isnumeric()
The isnumeric() method 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.
```
input: '1235'
Output : True
input: '12b3o5'
Output : False 
```
## - isspace( )
The isspace() methods returns “True” if all characters in the string are whitespace characters, Otherwise, It returns “False”.
```
Input : string = '\n \n \n'
Output : True
Input : string = 't\n h\n e\n'
Output : False
```
## - istitle( )
The istitle() method 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. The function "istitlte()" does not take any parameter!
```
input : string = 'Hello'
print(text.istitle())
Output: True
input : string = 'hello'
print(text.istitle())
Output: False
```
## - isprintable( )
The isprintable() method returns true if all the characters are printable, otherwise false.
```
input : string = 
'Hello'
Output: True
input : string = 
'Hello!\nAre you #1?'
Output: False
```
## - isupper() 
The isupper() methods returns true if all characters in the string are uppercase otherwise, It returns false. The function "isupper()" does not take any parameter!
```
Input : string 'HASHNODE'
Output : True
Input : string  'hashnode'
Output : False
```
## - islower( )
The islower() methods returns true if all characters in the string are lowercase otherwise, It returns false
This function is used to check if the argument contains any lowercase characters
```
Input : string = 'python'
Output : True
Input : string = 'Python' Output : False
```
## - upper( )
The upper() methods returns the uppercased string from the given string. It converts all lowercase characters to uppercase. If no lowercase characters exist, it returns the original string.
```
Input : string = 'coding'
Output : CODING
Input : string = 'CODING'
Output : CODING
```
## - lower()
The lower() methods returns the lowercased string from the given string. It converts all uppercase characters to lowercase. If no uppercase characters exist, it returns the original string.
```
Input : string = 'PYTHONISTA'
Output : pythonista
Input : string = 'PythoNista'
Output : pythonista
```

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