Python Installation

There are two ways to download and install Python

Download Python from its official website. You have to manually install libraries.
Download Anaconda. It comes with python and also popular python modules.

Useful commands:

pip list	To get the installed packages
python – – version	To check the python version
pip show pandas	To display Pandas Version
print(pandas.__version__)	To display Pandas Version
pandas.show_versions()	It comprises info about hosting OS, Pandas version, and versions of other installed packages
pip install pandas	To upgrade the Pandas module
pip install – – upgrade pandas – – user	To upgrade the Pandas module
conda – – version	To display conda version
conda env list	To display conda environment list
conda activate base	To activate base conda environment
conda deactivate	Deactivate all conda environments

Python Datatypes

Type	Description	Sample Values	Create	Access Variable & its Value
string	ordered, immutable, collection datatype	‘a’, ‘london’, ‘lon123’ , ‘how are you’	‘a’ or “he’s”	Refer appendix below
list	ordered, mutable, collection datatype list can have different datatype Accessing element in a list by referring its index	[‘a’, 1, 3.5, ‘Hello’]	list( ) or [ ]	e.g. var_lst[0] out: ‘a’ Refer appendix for more details
tuple	ordered, immutable, collection datatype often used for objects belong together. can’t create a tuple with single value i.e. then it is called as string. To create a tuple with single value add comma at the end. e.g. (‘a’,) When passing multiple values to the variable then automatically it create a tuple.		( ) – optional
set	unordered, mutable, no duplicate		set( ) or { }
dictionary	unordered, mutable, collection datatype key value pair mutable – value of the key can be overwrritten	dict_var={“name”:”Ravi”, “location”:”London”} or dict_var=dict(name=”Ravi”, location=”London”) Note: 2nd method don’t need double quotes and “=” symbol used instead of “:”	dict() or { : }	dict_var[“name”] If no key then we get key don’t exist error or dict_var.get(“name”) If no key nothing gets outputted and won’t cause any key error.

Note: Mutable – can change / changeable, and immutable is opposite to mutable.

Pandas Datatypes

Int64	Int
float64	Float
object	str or mixed (e.g. numeric and non numeric)
boolean	True/False

Appendix:

Accessing String variable sample:

List and also Error handling

Note: Some of the topics listed to be updated later

Python List

Datatypes in python¶

int
string
tuple
list
set
dictionary
boolean

List in python¶

collection datatype
allow duplciates
ordered
mutable
list can accomodate different datatypes inside the list

Topics¶

Create
add items or remove items
iterate list or accessing items inside the list
list slicing
list copy
transform the items inside the list (list comp)
destroy
Use case

Create¶

In [2]:

# empty list creation - can add items to teh list at a later stage
lst=[]

In [5]:

# empty list creation - Another way
lst=list()

In [6]:

type(lst)

Out[6]:

list

In [7]:

len(lst)

Out[7]:

In [10]:

lst.append(10)

In [15]:

lst

Out[15]:

[10]

In [16]:

lst.append('rrr')

In [17]:

lst

Out[17]:

[10, 'rrr']

In [27]:

lst=[20,'ddd',300]

In [28]:

lst

Out[28]:

[20, 'ddd', 300]

Add Items to the list¶

In [29]:

#Append add valiues at the end
lst.append(10)
lst

Out[29]:

[20, 'ddd', 300, 10]

In [30]:

#To add values to the specific position -use "insert" instead of "append"
lst.insert(2,'hello')
lst

Out[30]:

[20, 'ddd', 'hello', 300, 10]

In [31]:

# remove the last element in a list
lst.pop()
lst

Out[31]:

[20, 'ddd', 'hello', 300]

Remove items to the list¶

In [32]:

# to remove an value from a list
lst.remove('ddd')
lst

# caution will get a value error if the given value is not present

Out[32]:

[20, 'hello', 300]

Error Handling¶

In [44]:

# we already deleted 'ddd' and lets try to issue the remove again and catch that error

lst=[20,300]

try:
    lst.remove('ddd')
    print(lst)
except ValueError as e:
    print(e)
    print("Error: given value is not there in the list")
except Exception as e:
    print(e)
    print("Some error occurred")
    
else: # if success
    print(lst)
    
finally:
    print('Program reaches to the finally block')
    
print("Bye")
    

list.remove(x): x not in list
Error: given value is not there in the list
Program reaches to the finally block
Bye

In [43]:

lst=[20,300]

try:
    lst.remove(300)
    print(lst)
except ValueError as e:
    print(e)
    print("given value is not there in the list")
except Exception as e:
    print(e)
    print("Some error occurred")
else: # if success
    print(lst)
    
finally:
    print('Program reaches to the finally block')
    
print("Bye")

[20]
[20]
Program reaches to the finally block
Bye

In [ ]:

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