>>> # This is a comment
>>> # print("Hello World!")
...
>>>
False class finally is return
None continue for lambda try
True def from nonlocal while
and del global not with
as elif if or yield
assert else import pass
break except in raise
>>> a = 12
>>> type(a)
<class 'int'>
>>> a = 1.0
>>> type(a)
<class 'float'>
>>> a = "Hello World"
>>> type(a)
<class 'str'>
>>> 'World'
'World'
>>> "World"
'World'
>>> 'World\'s Best'
"World's Best"
>>> "World's Best"
"World's Best"
>>> number = int(input("Enter a number: "))
Enter a number: 5
>>> print(number)
5
name = str(input("Enter your name: "))
Enter your name: root
>>> print(name)
>>> a, b = 4, 5
>>> a
4
>>> b
5
>>> a, b = b, a
>>> a
5
>>> b
4
- Mathematical
+, -, /, %, * - Logical
and, or - Relational
<, <=, >, >=, ==, !=
a = 9
b = 12
c = 3
x = a - b / 3 + c * 2 - 1
y = a - b / (3 + c) * (2 - 1)
z = a - (b / (3 + c) * 2) - 1
print("X = ", x)
print("Y = ", y)
print("Z = ", z)
float(string) -> float value
int(string) -> integer value
str(integer) -> string representation
str(float) -> string representation
>>> a = 8.126768
>>> str(a)
'8.126768'
>>> name = 'Yongyuan'
>>> country = 'China'
>>> print("%s is from %s" % (name, country))
Yongyuan is from China
>>> print("{0} is from {1}".format(name, country))
Yongyuan is from China
>>> print("{} is from {}".format(name, country))
Yongyuan is from China
>>> print("{} is from {}".format(name))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IndexError: tuple index out of range
if expression:
do this
elif expression:
do this
else:
do this
if x == True:
do not this
if x == False:
do not this
if x:
do this
if not x:
do this
while condition:
statement1
statement2
>>> # Print 0-10
>>> n = 0
>>> while n < 11:
... print(n)
... n += 1
for iterating_var in sequence:
statement
>>> for i in range(0, 11): # Print 0-10
... print(i)
>>> sum = 0
>>> n = 10
>>> for i in range(1, n):
... sum += i
...
>>> print(sum)
45
>>> word = "Python2 Programming"
>>> for letter in word:
... if letter == "2":
... break
... print(letter)
...
P
y
t
h
o
n
>>> word = "Python3 Programming"
>>> for letter in word:
... if letter == "3":
... continue
... print(letter)
...
P
y
t
h
o
n
P
r
.
- List
- Tuple
- Dictionary
- Set
- String
Supports multiple datatypes
>>> list = [1, 2, "hello", 1.0]
>>> list
[1, 2, 'hello', 1.0]
>>> a = [23, 45, 1, -3434, 43624356, 234]
>>> a.append(45)
>>> a
[23, 45, 1, -3434, 43624356, 234, 45]
>>> a.insert(0, 111) # Inserts 111 at 0th Position
>>> a
[111, 1, 23, 45, 1, -3434, 43624356, 234, 45]
>>> a.count(45)
2
>>> a.remove(234)
>>> a
[111, 1, 23, 45, 1, -3434, 43624356, 45]
>>> b = [45, 56, 90]
>>> a.append(b)
>>> a [45, 43624356, -3434, 1, 45, 23, 1, 111, [45, 56, 90]]
>>> a[-1]
>>> [45, 56, 90]
>>> a.extend(b) #To add the values of b not the b itself
>>> a
[45, 43624356, -3434, 1, 45, 23, 1, 111, [45, 56, 90], 45, 56, 90]
>>> a[-1]
90
>>> a.remove(b)
>>> a
[45, 43624356, -3434, 1, 45, 23, 1, 111, 45, 56, 90]
>>> a.sort()
>>> a
[-3434, 1, 1, 23, 45, 45, 45, 56, 90, 111, 43624356]
>>> a = [1, 2, 3, 4, 5, 6]
>>> a
[1, 2, 3, 4, 5, 6]
>>> a.pop() # Pop Operation
6
>>> a.pop()
5
>>> a.pop()
4
>>> a
[1, 2, 3]
>>> a.append(34) # Push Operation
>>> a
[1, 2, 3, 34]
>>> a.append(1)
>>> a
[1, 2, 3, 34, 1]
>>> a = [1, 2, 3]
>>> [x ** 2 for x in a]
[1, 4, 9]
>>> z = [x + 1 for x in [x ** 2 for x in a]]
>>> z
[2, 5, 10]
>>> a = 'Fedora', 'Debian', 10, 12
>>> a
('Fedora', 'Debian', 10, 12)
>>> a[1]
'Debian'
>>> for x in a:
... print(x, end=' ')
...
Fedora Debian 10 12
>>> type(a)
<class 'tuple'>
>>> len(a)
4
>>> a = (1, 2, 3, 4)
>>> del a[0]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'tuple' object doesn't support item deletion
>>> a = (1, 2, 3) # Packing
>>> (first, second, third) = a # Unpacking
>>> first
1
>>> second
2
>>> third
3
>>> (first, second, third) = (1, 2, 3) # Another way
>>> data = {'quentin':'Fedora', 'diwen':'Debian', 'steve':'Mac'}
>>> data
{'quentin': 'Fedora', 'steve': 'Mac', 'diwen': 'Debian'}
>>> data['steve']
'Mac'
>>> data['gerard'] = 'Fedora'
>>> data
{'gerard': 'Fedora', 'quentin': 'Fedora', 'steve': 'Mac', 'diwen': 'Debian'}
>>> del data['steve']
>>> data
{'gerard': 'Fedora', 'quentin': 'Fedora', 'diwen': 'Debian'}
>>> for x, y in data.items():
... print("%s uses %s" % (x, y))
...
gerard uses Fedora
quentin uses Fedora
diwen uses Debian
>>> a = set('abcthabcjwethddda')
>>> a
{'a', 'c', 'b', 'e', 'd', 'h', 'j', 't', 'w'}
>>> a.add('p')
>>> a
{'a', 'c', 'b', 'e', 'd', 'h', 'j', 'q', 'p', 't', 'w'}
>>> a = [1, 2, 3, 4, 5, 6, 7]
>>> a[1:4]
[2, 3, 4]
>>> a[:-1]
[1, 2, 3, 4, 5, 6]
>>> a[::-1]
[7, 6, 5, 4, 3, 2, 1] # Reverse
>>> a = (1, 2, 3, 4, 5, 6, 7)
>>> a[1:4]
(2, 3, 4)
>>> a[::-1]
(7, 6, 5, 4, 3, 2, 1)
>>> a = 'Hello World'
>>> a[0]
'H'
>>> a[5]
' '
>>> a[1:]
'ello World'
>>> a[::-1] # Reverse
'dlroW olleH'
>>> s = "I am Dutch"
>>> s
I am Dutch'
>>> s = "Here is a line \
... split in two lines"
>>> s
'Here is a line split in two lines
>>> s = """ This is a
... multiline string, so you can
... write many lines"""
>>> print(s)
This is a
multiline string, so you can
write many lines
>>> s = "gerard braad"
>>> s.title()
'Gerard Braad'
>>> z = s.upper()
>>> z
'GERARD BRAAD'
>>> z.lower()
'gerard braad'
>>> s = "123"
>>> s.isdigit()
True
>>> s = "Fedora24"
>>> s.isdigit()
False
>>> s = "Let's learn Python3"
>>> s.split(" ")
["Let's", 'learn', 'Python3']
>>> s.split()
["Let's", 'learn', 'Python3']
>>> s = "This is: ME"
>>> s.split(":")
['This is', ' ME']
>>> s = "We all love Python."
>>> s.split(".")
['We all love Python', '']
>>> "3".join(s.split("."))
'We all love Python3'
>>> s = " abc "
>>> s.strip()
'abc'
>>> # Strip from left hand and right hand size
>>> s = "www.fedoraproject.org"
>>> s.lstrip("www.")
'fedoraproject.org'
>>> s.rstrip(".org")
'www.fedoraproject'
>>> for i, j in enumerate(['a', 'b', 'c']):
... print(i, j)
...
0 a
1 b
2 c
def functionname(params):
statement1
statement2
>>> def sum(a, b):
... return a + b
>>> res = sum(2, 3)
>>> res
5
>>> def check_palindrome(word):
... rev_word = word[::-1]
... if word == rev_word:
... print("Palindrome")
... else:
... print("Not Palindrome")
...
>>> check_palindrome("madam")
Palindrome
>>> check_palindrome("python3")
Not Palindrome
>>> def test(a , b=-99):
... if a > b:
... return True
... else:
... return False
>>> test(12, 23)
False
>>> test(12)
True
>>> def func(a, b=5, c=10):
... print('a is', a, 'and b is', b, 'and c is', c)
...
>>> func(12)
a is 12 and b is 5 and c is 10
>>> func(12, 24)
a is 12 and b is 24 and c is 10
>>> func(12, c = 25)
a is 12 and b is 5 and c is 25
>>> func(a=12)
a is 12 and b is 5 and c is 10
Note: Can not have non-keyword argument after a keyword based argument
r - Open with read only mode
w - Open with write mode
a - Open with append mode
>>> f = open('sample.txt', 'r')
>>> f.read()
"Hello World.\nLet's learn Python3.\n"
>>> f.close()
>>> f = open('sample.txt', 'r')
>>> f.readline()
'Hello World.\n'
>>> f.readline()
"Let's learn Python3.\n"
>>> f.close()
>>> f = open('sample.txt', 'r')
>>> f.readlines()
['Hello World.\n', "Let's learn Python3.\n"]
>>> f.close()
>>> f = open('sample.txt', 'r')
>>> for i in f:
... if 'Python' in i:
... print(i)
... f.close()
Let's learn Python3.
>>> f = open('test.txt', 'w') # Write
>>> f.write("Hello world")
>>> f.close()
>>> f = open('test.txt', 'r')
>>> f.read()
'Hello world'
>>> f.close()
>>> f = open('test.txt', 'a') # Append
>>> f.write(" Python')
>>>f.close()
>>> f = open('test.txt', 'r')
>>> f.read()
"Hello world Python"
>>>f.close()
>>> with open('sample.txt', 'r') as f:
... f.read()
...
"Hello World.\nLet's learn Python3.\n"
>>> with open('sample.txt', 'r') as f:
... for i in f:
... if 'Python' in i:
... print(i)
...
Let's learn Python3.
- import module
- from module import something
- from module import *
math.py
def square(x):
return x * x
result.py
from math import square
print(square(5))
math.py
def square(x):
return x * x
if __name__ == '__main__':
print("Result: for square(5) == %d " % square(5))
result.py
import math
print(math.square(5))