add_python_lesson_1

python_lesson_1.py

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+print("hello world")
+
+"""to check python version
+import sys
+print(sys.version)
+"""
+#variables
+x = 5
+y = "hello sai!"
+print(y , x)
+
+#casting for speecifying data type
+x = int(4)
+y = str("sai")
+z = float(4)
+s = x + z
+print (s)
+
+#type() function
+print(type(s))
+
+#multiple value assign to multiple variables
+x , y , z = "orange" , "apple", "papaya"
+print(x,y,z)
+
+#one value to multiple variables
+x = y = z = "alphanso mango"
+print(x)
+print(y)
+print(z)
+
+#unpack a collection 
+fruits = ["raspberry" , "gauva" , "mango"]
+x, y, z = fruits
+print(x)
+print(y)
+print(z)
+
+# + operator adds for int and concatenate for string
+print( 20 + 12)
+print("sai" + "deshmane")
+
+#global variable
+x = "awesome"
+def myfunction():
+    print("python is" + x);
+
+myfunction
+
+#local & global having same name , variable unside func called as local 
+x = "awesome"
+def myfunc():
+    x = "fantastic"
+    print("python is" + x)
+
+myfunc()
+print("python is" + x)
+
+#but we declare variable as global inside a function
+def myfunct():
+    global x
+    x = "damnnnnnn"
+myfunct()
+print("python is " + x)
+
+#we can also change global variable (here awesome is overwrite by fantasticcc)
+x = "awesome"
+def myfun():
+    global x
+    x = "fantasticcccc"
+myfun()
+print("python is" + x)
+
+#boolean type
+sai = True
+print(sai)
+print(type(sai))
+
+#list
+x = ["sai" , "vishu" , "vishwa"]
+print (x)
+print(x[2])
+
+#tuple(immutable)
+x = ("sai" , "vishu", "vishwa")
+print(x)
+print(x[0])
+
+#range
+y = 8
+x = range(y)
+print(x)
+print(type(x))
+
+#dictionary
+x = {"name" : "john" , "age" : 36}
+print(x)
+print(type(x))
+
+#set
+x = {"apple" , "banana" , "cherry"}
+print(x)
+print(type(x))
+
+#frozenset
+
+x = frozenset({"apple" , "banana", "watermelon"})
+print(x)
+print(type(x))
+
+x = 1   #int
+x = 1.0 #float
+x = 1j  #complex
+
+#e indicates power of 10, number contaoning is float
+x = 10e1
+print(x)
+
+#complex with j as imaginary part
+x = 3+5j
+print(x)
+print(type(x))
+
+
+#type conversion 
+x = 1    # int
+y = 2.8  # float
+z = 1j   # complex
+
+#convert from int to float:
+a = float(x)
+
+#convert from float to int:
+b = int(y)
+
+#convert from int to complex:
+c = complex(x)
+
+print(a)
+print(b)
+print(c)
+
+print(type(a))
+print(type(b))
+print(type(c))
+
+#random module
+import random
+print(random.randrange(1, 100))
+
+#multiline string 
+a = """hey im sai and i jst 143<3 mauuu """
+print(a)
+print(len(a))
+
+#check if certain character or phrase is in string or not using keyword 'in'
+txt = ["sai" , "vishu", "vishwa"]
+if "sai" in txt:
+    print(True)
+
+#To check if a certain phrase or character is NOT present in a string, 
+# we can use the keyword not in
+txt = ["sai" , "vishu", "vishwa"]
+if "vishwajeet" not in txt:
+    print(False)
+
+#slicing char at 11 not included means printed from index 6 to 10 only
+b = "hello world"      
+print(b[6:11])
+print(b[:6]) #print from start idx i.e 0 to 5
+print(b[2:]) #print from idx 2 to end
+
+#-11 -10-9 -8 -7 -6 -5 -4 -3 -2 -1           
+#  h  e  l  l  o  w  o  r  l  d  !
+#  0  1  2  3  4  5  6  7  8  9  10 11
+
+b = "hello world!"
+print(b[-5:-2])
+
+#upper()
+a = "sai"
+print(a.upper())
+
+#lower()
+a = "sai"
+print(a.lower())
+
+# strip() method removes any whitespace from the beginning or the end
+a = "  sai  "
+print(a.strip())
+
+#replace() method replaces a string with another string
+a = "sai"
+print(a.replace("sai" ,"vishu"))
+
+#split() method splits the string into substrings if it finds instances of the separato
+a = "Hello, World!"
+print(a.split(","))
+
+# we can combine strings and numbers by using f-strings or the format() method!
+age = 21
+txt = f"my age is {age}"
+print(txt)
+
+#A placeholder can contain variables, operations, functions, and
+# modifiers to format the value.
+#Add a placeholder for the price variable
+price = 59
+txt = f"the price is {price}"
+print(txt)
+
+#Display the price with 2 decimals, colon : followed by a legal formatting type, like .2f
+price = 59
+txt = f"the price is {price :.2f}"
+print(txt)
+
+# placeholder can contain Python code, like math operations
+txt = f"the price is {20 * 20}"
+print(txt)
+
+# to insert characters the are illegeal in a string,use an escape character
+#1. \"
+txt = "sai is a \"viking\" "
+print(txt)
+
+# 2.\' 
+# txt = 'sai is a \'viking\' '
+print(txt)
+
+#3.\\ (enters one backslash)
+txt = "this will insert one\\ backslash"
+print(txt)
+
+#4.\n (for new line)
+txt = "sai is \n viking"
+print(txt)
+
+#5.\r (Carriage Return)
+txt = "Hello\rworld!"
+print(txt)
+
+#6.\t (Tab)
+txt = "hello \t world"
+print(txt)
+
+#7.\b (Backspace)
+txt = "hello \b world"
+print(txt)
+
+#8.\f (Form Feed)
+txt = "hello \f world"
+print(txt)
+
+#A backslash followed by an 'x' and a hex number represents a hex value:
+txt = "\x48\x65\x6c\x6c\x6f"
+print(txt) 
+
+#string methods
+
+#count() Returns the number of times a specified value occurs in a string
+txt = "hello world!"
+print(txt.count('l'))
+
+#ccasefold() Converts string into lower case
+txt = "HELLO world!"
+print(txt.casefold())
+
+#endswith() Returns true if the string ends with the specified value
+txt = "hello world!"
+print(txt.endswith('!'))
+
+#find()	Searches the string for a specified value and returns the position of where it was found
+txt = "hello world!"
+print(txt.find('o'))
+
+#index()	Searches the string for a specified value and returns the position of where it was found
+txt = "hello world!"
+print(txt.index('o'))
+
+#isdecimal() Returns True if all characters in the string are decimals
+txt = "hello world!"
+print(txt.isdecimal())
+
+#more methods based on string check on w23 school
+
+#boolean 
+print(10 > 9)
+print(10 < 9)
+print(10 == 9)
+
+#bool() function allows you to evaluate any value, and give you True or False in return,
+print(bool("hello"))
+print(bool(15))
+
+#evalute the two variables
+x = "hello"
+y = 15
+print(bool("hello"))
+print(bool(15))
+
+#Almost any value is evaluated to True if it has some sort of content.
+#Any string is True, except empty strings.
+#Any number is True, except 0.
+#Any list, tuple, set, and dictionary are True, except empty ones.
+
+#The following will return True:
+print(bool("abc"))
+print(bool(123))
+print(bool(["apple", "cherry", "banana"]))
+
+#The following will return False:
+print(bool(False))
+print(bool(None))
+print(bool(0))
+print(bool(""))
+print(bool(()))
+print(bool([]))
+print(bool({}))
+
+#One more value, or object in this case, evaluates to False, and that is if you have 
+# an object that is made from a class with a __len__ function that returns 0 or False
+class myclass():
+    def __len__(self):
+        return 0
+myobj = myclass()
+print(bool(myobj))
+
+#Print the answer of a function:
+def myFunction() :
+  return True
+print(myFunction())
+
+#Print "YES!" if the function returns True, otherwise print "NO!":
+def myFunction() :
+  return True
+if myFunction():
+  print("YES!")
+else:
+  print("NO!")
+
+#Check if an object is an integer or not:
+x = 200
+print(isinstance(x, int))
+
+a = "hello world"
+print(a[1])
+
+for x in "hello world":
+    print (x)
+
+a = "hello world"
+print(len(a))
+
+#Print only if "free" is present
+txt = "sai"
+list = txt
+if 'a' in txt:
+  print(txt.index('a'))
+
+#Check if "expensive" is NOT present in the following text
+txt = "i am sai"
+print("sai" not in txt)
+if "vishwa" not in txt:
+    print("vishwa in not present")