Python: Difference between revisions

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=links=
=version=
  http://en.wikibooks.org/wiki/Non-Programmer%27s_Tutorial_for_Python_2.6
Show python version
  http://docs.python.org/tutorial
  python -V
Reference
=make an http request=
  http://docs.python.org/ref/ref.html
import requests
r =requests.get('https://halfface.se')
  print(r.text)
=dictionary=
  dictionary = {"a": 99, "hello": "world"}


=basics=
=import=
 
Import functions.
  print "Hello, World!"
  import $module
command called print followed by one argument,which is "Hello, World!". (referred to as a string of characters, or string) Command and its arguments are collectively referred to as a statement,
=try:=
 
Exception handling. Example will fail because x is unset.
  print "2 + 2 is", 2 + 2
try:
The first argument is the string "2 + 2 is" and the second argument is the mathematical expression 2 + 2, which is commonly referred to as an expression. each of the arguments separated by a comma
  print(x)
except:
  print("An exception occurred")
=sys.exit()=
exits and no stack traceback is printed.
=re=
Regular expression searching
ip = re.findall(r'[0-9]+(?:\.[0-9]+){3}', config_info)
=join elements in list for other output=
  print(', '.join(configured_ip_addresses))
=for loop=
fruits = ["apple", "banana", "cherry"]
for x in fruits:
  print(x)
=range=
for i in range(0,Loops,1):
    print("Value")


sys.argv  arguments are passed to the script in the variable sys.argv
=input=
  #          is used to start a comment
Read a value from prompt into variable number.
=operations for numbers=
  number=int(input("Please give me a number? "))
{| class="wikitable"
=append=
! Operation
Append values to grades
! Symbol
  grades.append(int(input("Please give me the grade? ")))
! Example
=format=
|-
Use variable i input question string.
|Power (exponentiation)
  sales = float(input("Please enter your sales from day {}".format(x)))
| <code>**</code>
=round, number of decimals=
| <code>5 ** 2 == 25</code>
  print(round(AverageGrades),1)
|-
=debug/trace=
|Multiplication
  python -m trace --trace script.py
| <code>*</code>
=virtualenvwrapper=
|<code>2 * 3 == 6</code>
enter
|-
  workon
|Division
exit
| <code>/</code>
  deactivate
| <code>14 / 3 == 4</code>
|-
|Remainder (modulo)
| <code>%</code>
| <code>14 % 3 == 2</code>
|-
|Addition
| <code>+</code>
| <code>1 + 2 == 3</code>
|-
|Subtraction
| <code>-</code>
| <code>4 - 3 == 1</code>
|}
=userinput=
raw_input (returns a string)
  user_reply = raw_input("Who goes there? ")
 
input (returns digits)
number = input("Type in a number: ")
type(number) (tells what a variable is.)
print "number is a", type(number)
=while loop=
print number interval. finish while loop with a ':' The while statement only affects the lines that are indented with whitespace.
  start = input("Start number? ")
stop = input("Stop number? ")
a = start
while a < stop:
    print a
    a = a + 1
{| class="wikitable"
!operator
!function
|-
|<code><</code>
|less than
|-
|<code><=</code>
|less than or equal to
|-
|<code>></code>
|greater than
|-
|<code>>=</code>
|greater than or equal to
|-
|<code>==</code>
|equal
|-
|<code>!=</code>
|not equal
|-
|<code><></code>
|another way to say not equal (old style, not recommended)
|}
 
=if statment=
  if a > 5: 
    print a, ">", 5
  elif a <= 7:
    print a, "<=", 7
  else:
    print "Neither test was true"
 
# This Program Demonstrates the use of the == operator  # using numbers
  print 5 == 6
false
=functions=
The key feature of this program is the def statement. def (short for define) starts a function definition. def is followed by the name of the function absolute_value. Next comes a '(' followed by the parameter n (n is passed from the program into the function when the function is called). The statements after the ':' are executed when the function is used. The statements continue until either the indented statements end or a return is encountered. The return statement returns a value back to the place where the function was called.
def absolute_value(n):
  if n < 0:
    n = -n
  return n
=import=
==Sleep==
  import time
time.sleep(secs)
==random==
import random
  number = random.randrange(1, 100, 1)
==list==
list with more than one value.which_one = input("What month (1-12)? ")
  months = ['January', 'February', 'March', 'April', 'May', 'June', 'July',          'August', 'September', 'October', 'November', 'December']  if 1 <= which_one <= 12:    print "The month is", months[which_one - 1]

Latest revision as of 10:51, 10 September 2024

version

Show python version 

python -V

make an http request

import requests
r =requests.get('https://halfface.se')
print(r.text)

dictionary

dictionary = {"a": 99, "hello": "world"}

import

Import functions. 

import $module

try:

Exception handling. Example will fail because x is unset. 

try:
  print(x)
except:
  print("An exception occurred")

sys.exit()

exits and no stack traceback is printed.

re

Regular expression searching 

ip = re.findall(r'[0-9]+(?:\.[0-9]+){3}', config_info)

join elements in list for other output

print(', '.join(configured_ip_addresses))

for loop

fruits = ["apple", "banana", "cherry"]
for x in fruits:
  print(x)

range

for i in range(0,Loops,1):
    print("Value")

input

Read a value from prompt into variable number. 

number=int(input("Please give me a number? "))

append

Append values to grades 

grades.append(int(input("Please give me the grade? ")))

format

Use variable i input question string. 

sales = float(input("Please enter your sales from day {}".format(x)))

round, number of decimals

print(round(AverageGrades),1)

debug/trace

python -m trace --trace script.py

virtualenvwrapper

enter 

workon

exit 

deactivate
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