Python : special tricks & short cuts ( let's catch the snake!!)

Python Editor keyboard shortcuts:

Keyboard Shortcut?????????? ????????? Command??????????? ?? ??????????????????Description

Ctrl+T ?????????????????????????????????????Create work area.?????????????? Creates a tab in the

work area of the

Python Editor for the

new script.

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Ctrl+O?????????????????????????????????????? Load script. Loads the selected

script in the Python Editor

work area.

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Ctrl+- Close script. Closes the active

script in the Python

Editor work area.

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Ctrl+S Save active script. Saves the active script.

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Ctrl+F2 Save new active script. Saves the new active

script.

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F5 Execute active script. Executes code or a script, depending on whether a code is highlighted. If nothin highlighted, it executes the active script in the Python Editor work area.

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Ctrl+= Add active script to scene. Adds the active script to the scene. See the scene browser Scripts directory.

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F10 Display Python Tool Manager. Displays the Python Tool Manager.

F1 Trigger Python Editor context help. Displays help related to current action.

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Ctrl+F Find code. Finds the term specified in the interactive console’s text field.

?F3 Find subsequent code. Finds the next instance of the term specified in the interactive console’s text

?Ctrl+H Find and replace code. Displays the

Search and Replace dialog where you can either choose to find or find and replace text in the active script.

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Ctrl+G Go to line. Activates the interactive console text field where you enter the line number you want to go to in the active script.

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Alt+N Go to next command. In the interactive console, traverses history by entering the first command.

?Alt+P Go to previous command. In the interactive console, traverses history by entering the previous

command.

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Tab Indent text block. Indents code block to be entered in the

active script.

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Alt+C Comment selected code. Comments selected code in the active script.

Alt+U Uncomment selected code. Uncomments

selected code in the

active script.

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Ctrl+Space Auto-complete entry. Auto-completes the

instantiated class.

Top Python tricks for efficient programming:

To keep things simple and transparent, the tricks have been categorized based on a few key aspects such as lists, strings, matrix, dictionary, etc.

Lists

Trick 1: Flatten the lists

import itertools

a = [[1, 2], [3, 4], [5, 6]]

b = list(itertools.chain.from_iterable(a))

print(b)

Output:

[1, 2, 3, 4, 5, 6]

Trick 2: Reverse a list

a=[“10”,”9",”8",”7"]

print(a[::-1])

Output:

10

9

8

7

Trick 3: Combining different lists

a=[‘a’,’b’,’c’,’d’]

b=[‘e’,’f’,’g’,’h’]

for x, y in zip(a, b):

print(x,y)

Output:

a e

b f

c g

d h

Trick 4: Negative indexing lists

a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

a[-3:-1]

Output:

[8, 9]

Trick 5: Analyzing the most frequent on the list

a = [1, 2, 3, 4, 2, 2, 3, 1, 4, 4, 4]

print(max(set(a), key = a.count))

Output:

4

Strings

Trick 6: Reversing the string

a=”python”

print(“Reverse is”, a[::-1])

Output:

Reverse is nohtyp

Trick 7: Splitting the string

a="Python is the language of the future"

b=a.split()

print(b)

Output:

[‘Python’, ‘is’, ‘the’, ‘language’, ‘of’, 'the’, ‘future’]

Trick 8: Printing out multiple values of strings

print(“on”*3+’ ‘+”off”*2)

Output:

ononon offoff

Trick 9: Creating a single string

a = [“I”, “am”, “not”, “available”]

print(“ “.join(a))

Output: I am not available

Trick 10: Checking if two words are anagrams

from collections import Counter

def is_anagram(str1, str2):

return Counter(str1) == Counter(str2)

print(is_anagram(‘taste’, ‘state))

print(is_anagram(‘beach’, ‘peach’))

Output:

True

False

Matrix

Trick 11: Transposing a matrix

mat = [[8, 9, 10], [11, 12, 13]]

new_mat=zip(*mat)

for row in new_mat:

print(row)

Output:

(8, 11)

(9, 12)

(10, 13)

Operators

Trick 12: Chaining comparison operators

a = 17

b = 21

c = 11

print(c < a)

print(a < b)

Output:

True

True

True

Dictionary

Trick 13: Inverting the Dictionary

dict1={‘a’: 1, ‘b’: 2,‘c’: 3,‘d’: 4,‘e’: 5,‘f’: 6, ‘g’: 7}

dict2={v: k for k, v in dict1.items()}

print(dict2)

Output:

{1: ‘a’, 2: ‘b’, 3: ‘c’, 4: ‘d’, 5: ‘e’, 6: ‘f’, 7: ‘g’}

Trick 14: Iterating value pairs and dictionary keys

dict1={‘a’: 1, ‘b’: 2, ‘c’: 3, ‘d’: 4, ‘e’: 5, ‘f’: 6}

for a, b in dict1.iteritems():

print (‘{: {}’.format(a,b))

Output:

a: 1

b: 2

c: 3

d: 4

f: 6

Trick 15: Merging multiple dictionaries

x = {'a': 1, 'b': 2}

y = {'b': 3, 'c': 4}

z = {**x, **y}

print(z)

Output:

{‘a’: 1, ‘b’: 3, ‘c’: 4}

Initialization

Trick 16: Initializing empty spaces

a_list = list()

a_dict = dict()

a_map = map()

a_set = set()

Trick 17: Initializing lists filled with numbers

#listA contains 1000 1's

listA=[1]*1000

#listB contains 1000 2's

listB=[2]*1000

Miscellaneous

Trick 18: Checking and analyzing the memory unit of an object

import sys

a=10

print(sys.getsizeof(a))

Output: 28

Trick 19: Swapping values

x, y = 13, 26

x, y = y, x

print(x, y)

Output:

26 13

Map functions

Trick 20: Implementing the map function

In competitive coding, you might come across an input like this:

1234567890

To get the input as a list of numbers, perform the following:

list(map (int, input().split()))

Note: Always use the input() function irrespective of the type of input and convert it using the map function.

>>> list(map(int, input("enter numbers:").split()))

enter numbers:1 2 3 4 5 6 7

[1, 2, 3, 4, 5, 6, 7] >>>

The map function is one of the most useful in-built functions and features of Python.

Collections module

Trick 21: Merging different lists

The Collections module allows you to remove duplicates from a list. In Java, you have to use the HashMap to remove duplicate modules, but it’s far easier in the case of Python.

>>> print(list(set([1,2,3,4,3,4,5,6,7,8,9])))

[1, 2, 3, 4, 5, 6, 7, 8, 9]

You need to use extend() and append() in the lists while merging multiple lists.

>>> a = [1, 2, 3, 4] # list 1

>>> b = [ 5, 6, 7, 8, 9] # list 2

Note: >>> a.extend(b) will display one list.

>>> a [1, 2, 3, 4]

Note: >>> a.append(b) will display the list of list.

>>> a [1, 2, 3, 4 [5, 6, 7, 8, 9]]

Language constructs

Trick 22: Writing code within functions

In Python, it is always better to write your code within functions.

def main():

for i in range(2**3):

print(x)

main()

The above code fragment is better than the one below:

for x in range(2**3):

print(x)

The CPython implementation saves time in the case of storing local variables.

Bonus tip

These useful Python tricks will help you code better and more efficiently. Here is a bonus tip that you should know and implement.

Strings concatenation

str1 = ""

some_list = ["Welcome ", "To ", "Bonus ", “Tips ”]

print(str1.join(some_list))

Use the above code instead of:

str1 = ""

some_list = ["Welcome ", "To ", "Bonus ", “Tips ”]

for x in some_list:

str1 += x

print(str1)

Speed and, most of all, efficiency, are key to coding better. By incorporating the tips outlined in this article, you can significantly improve your Python programming skills. Give them a try in your next competitive coding event or other Python projects and notice the difference they make.

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