Updating Readme and other examples

Kranthi · Kranthi · commit a5d1e3cdb13e · 2021-11-13T08:16:03.000-06:00
diff --git a/.gitignore b/.gitignore
@@ -1,4 +1,4 @@
-# Byte-compiled / optimized / DLL files
+# Byte-compiled / optimized / DLL files-examples
 __pycache__/
 *.py[cod]
 *$py.class
@@ -34,7 +34,7 @@ share/python-wheels/
 MANIFEST
 
 # PyInstaller
-#  Usually these files are written by a python script from a template
+#  Usually these files-examples are written by a python script from a template
 #  before PyInstaller builds the exe, so as to inject date/other infos into it.
 *.manifest
 *.spec
@@ -104,7 +104,7 @@ __pypackages__/
 celerybeat-schedule
 celerybeat.pid
 
-# SageMath parsed files
+# SageMath parsed files-examples
 *.sage.py
 
 # Environments
@@ -133,3 +133,4 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+main.py
diff --git a/README.md b/README.md
@@ -2,3 +2,37 @@
 This repository covers python basic foundations with examples and helps to understand the nuts and bolts of the language.
 
 ### The examples are based on 3.8.2 version
+
+# How to execute a python file from bash
+python ./name_of_python_file.py 
+
+## More detailed info on several different ways to execute the python from bash
+   * https://stackoverflow.com/questions/4377109/shell-script-execute-a-python-program-from-within-a-shell-script
+   
+## Why do we need a virtual environment and how to create virtual environment
+###### If you want your code to run in it's own virtual environment without depending on the OS virtual env or on other python interpreters then in those scenarios you need a virtual environment.
+    * python -m venv new_virt_env
+### Activate virtual environment 
+  *  source new_virt_env/bin/activate ( In Mac as /bin folder doesn't exists in windows)
+  *  new_virt_env/Scripts/activate ( In windows - Just run this path to activate the virtual environment)
+### Deactivate virtual environment and Destroy virtual environment
+  * deactivate
+  * rm -rf new_virt_env/ ( Clean up all the files in the folder)  
+  
+###### Pip installing and uninstalling new packages
+    * pip install selenium --user ( pass --user if pip install selenium fails)
+    * pip uninstall selenium
+    * pip uninstall selenium urllib3 ( to uninstall multiple packages)
+   
+###### Upgrading pip
+Upgrade pip if any of the package doesn't get installed in the virtual env
+
+    * python -m pip install --upgrade pip
+
+###### Other pip commands
+    * pip --help
+    * pip freeze ( Outputs the installed packages using pip)
+    * pip freeze > requirements.txt
+    * pip install -r requirements.txt ( Install required packages)
+
+
diff --git a/examples/BuiltInFunctions.py b/examples/BuiltInFunctions.py
@@ -18,3 +18,5 @@
 # String format of Integer..
 i = int('457')
 print('{}'.format('hello in integer:'), i + 2)
+
+
diff --git a/examples/basics/floating_conversions.py b/examples/basics/floating_conversions.py
@@ -0,0 +1,5 @@
+print('Welcome to python')
+a = '35'
+b = "45.26"
+c = float(b) * float(a)
+print('{}{}'.format('c is ', c))
diff --git a/examples/basics/python_executable.py b/examples/basics/python_executable.py
@@ -0,0 +1,2 @@
+#!/usr/bin/env python
+print("hello wlcome to python !!")
diff --git a/examples/dictionaries/nest_dictionaries.py b/examples/dictionaries/nest_dictionaries.py
@@ -6,7 +6,8 @@
 
 for name, languages in fav_lang.items():
     for langs in languages:
-        if len(langs) > 1:
+        #print('lang::{}and length:{}'.format(langs, len(langs)))
+        if len(languages) > 1:
             print("{} favourite languages  are:{} and length is::{}".format(name, langs, len(languages)))
         else:
             print("{} favourite lang is:{}".format(name, languages))
diff --git a/examples/files-examples/__init__.py b/examples/files-examples/__init__.py
diff --git a/examples/files-examples/file3.py b/examples/files-examples/file3.py
@@ -0,0 +1,9 @@
+
+# Count the number of lines in a file and printing lines.
+
+fd = open('../../files/text.file', 'r')
+count = 0
+for line in fd:
+    count = count +1
+    print('{}{}'.format('line from file is::', line))
+print('{}{}'.format('no of lines::', count))
diff --git a/examples/files-examples/files.py b/examples/files-examples/files.py
diff --git a/examples/files-examples/files2.py b/examples/files-examples/files2.py
diff --git a/examples/files-examples/read_lines.py b/examples/files-examples/read_lines.py
@@ -0,0 +1,28 @@
+fp = open('../../files/text.file', 'r')
+lines = fp.readlines()
+for line in lines:
+    print('{}{}'.format('lines are::', line.strip()))
+fp.close()
+
+# Get 5 characters from a line
+fp = open('../../files/text.file', 'r')
+line = fp.readline()
+typeis = type(line)
+
+print('{}{}'.format('stripped line:', line[:5]))
+
+# Get only 2 lines in the file.
+fp = open('../../files/text.file', 'r')
+line = fp.readlines()
+for each_line in line[:2]:
+    print('{}{}'.format('print each line:', each_line))
+
+fp.close()
+
+#
+fp = open('../../files/text.file', 'r')
+#line = fp.readline(2)
+#print('same line:', line)
+#same line: Welcome to python and this is the second
+print('same line:', fp.read(2))
+#print('file chars length:', len(line))
diff --git a/examples/functions.py b/examples/functions.py
@@ -3,9 +3,12 @@ def invokehellofunction():
     if int(x) > 100:
         print("this is a hello function !!")
     else:
-        print("x is not greater than 100")
+        str = "hello"
+        print(str + " x is not greater than 100")
     return "hello is returned !!"
 
 
 functionReturValue = invokehellofunction()
 print("{} {}".format("return value from function::", functionReturValue))
+
+print("does this print ever :::")
diff --git a/files/text.file b/files/text.file
@@ -1,2 +1,4 @@
 Hello this is a text file - first line
-Welcome to python and this is the second line
+Welcome to python and this is the second line
+Welcome to python and this is the Third Line
+Welcome to python and this is the Fourth Line

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+#!/usr/bin/env python`
	`2`	`+print("hello wlcome to python !!")`