Python Snippets

fStrings.py

#Formatting strings with f string.
str_val = 'books'
num_val = 15
print(f'{num_val} {str_val}') # 15 books
print(f'{num_val % 2 = }') # 1
print(f'{str_val!r}') # books

#Dealing with floats
price_val = 5.18362
print(f'{price_val:.2f}') # 5.18

#Formatting dates
from datetime import datetime;
date_val = datetime.utcnow()
print(f'{date_val=:%Y-%m-%d}') # date_val=2021-09-24

mergeDicts.py

from collections import defaultdict
#merge two or more dicts using the collections module
def merge_dicts(*dicts):
  mdict = defaultdict(list)
  for d in dicts:
    for key in d:
      mdict[key].append(d[key])
  return dict(mdict)
  
print(merge_dicts({'a':'One','c':'Three','f':{'g':'Five'}},{'b':'Two'}))
# {'a': ['One'], 'c': ['Three'], 'f': [{'g': 'Five'}], 'b': ['Two']}

mergeList.py

def merge(*args, missing_val = None):
#missing_val will be used when one of the smaller lists is shorter tham the others.
#Get the maximum length within the smaller lists.
  max_length = max([len(lst) for lst in args])
  outList = []
  for i in range(max_length):
    outList.append([args[k][i] if i < len(args[k]) else missing_val for k in range(len(args))])
  return outList
  
out = merge([1,2,3], ['a','b','c','z'], ['h','e','y'], missing_val='XXX')
print(out)
# [[1, 'a', 'h'], [2, 'b', 'e'], [3, 'c', 'y'], ['XXX', 'z', 'XXX']]

Snippets.MD

Python Snippets

sortDict.py

dicts_lists = [
  {
    "Name": "James",
    "Age": 20,
  },
  {
     "Name": "May",
     "Age": 14,
  },
  {
    "Name": "Katy",
    "Age": 23,
  }
]

#There are different ways to sort that list
#1- Using the sort/ sorted function based on the age
dicts_lists.sort(key=lambda item: item.get("Age"))

#2- Using itemgetter module based on name
from operator import itemgetter
f = itemgetter('Name')
dicts_lists.sort(key=f)

sortListByPriorityList.py

a = ['blue', 'green', 'orange', 'purple', 'yellow']
b = [3, 2, 5, 4, 1]
#Use list comprehensions to sort these lists
sortedList =  [val for (_, val) in sorted(zip(b, a), key=lambda x: \
          x[0])]
          
print(sortedList)

stringListSort.py

my_list = ["blue", "red", "green"]

#1- Using sort or srted directly or with specifc keys
my_list.sort() #sorts alphabetically or in an ascending order for numeric data 
my_list = sorted(my_list, key=len) #sorts the list based on the length of the strings from shortest to longest. 
# You can use reverse=True to flip the order

#2- Using locale and functools 
import locale
from functools import cmp_to_key
my_list = sorted(my_list, key=cmp_to_key(locale.strcoll))