This cheat sheet tries to provide a basic reference for beginner and advanced developers, lower the entry barrier for newcomers, and help veterans refresh the old tricks. (Full Python Cheat Sheet)

Lists

list = []
list[i:j] # returns list subset
list[-1] # returns last element
list[:-1] # returns all but the last element

list[i] = val
list[i:j] = otherlist # replace ith to jth-1 elements with otherlist
del list[i:j]

list.append(item)
list.extend(another_list)
list.insert(index, item)
list.pop() # returns and removes last element from the list
list.pop(i) # returns and removes i-th element from the list
list.remove(i) # removes the first item from the list whose value is i
list1 + list2 # combine two list
set(list) # remove duplicate elements from a list

list.reverse() # reverses the elements of the list in-place
list.count(item)
sum(list)

zip(list1, list2) # returns list of tuples with n-th element of both list1 and list2
list.sort() # sorts in-place, returns None
sorted(list) # returns sorted copy of list
",".join(list) # returns a string with list elements seperated by comma

Dict

dict.keys()
dict.values()
"key" in dict # let's say this returns False, then...
dict["key"] # ...this raises KeyError
dict.get("key") # ...this returns None
dict.setdefault("key", 1)

Iteration

for item in ["a", "b", "c"]:
for i in range(4): # 0 to 3
for i in range(4, 8): # 4 to 7
for i in range(1, 9, 2): # 1, 3, 5, 7
for key, val in dict.items():
for index, item in enumerate(list):

String

str[0:4]
len(str)

string.replace("-", " ")
",".join(list)
"hi {0}".format('j')
f"hi {name}" # same as "hi {}".format('name')
str.find(",")
str.index(",") # same, but raises IndexError
str.count(",")
str.split(",")

str.lower()
str.upper()
str.title()

str.lstrip()
str.rstrip()
str.strip()

str.islower()

/* escape characters */
>>> 'doesn\'t' # use \' to escape the single quote...
"doesn't"
>>> "doesn't" # ...or use double quotes instead
"doesn't"
>>> '"Yes," they said.'
'"Yes," they said.'
>>> "\"Yes,\" they said."
'"Yes," they said.'
>>> '"Isn\'t," they said.'
'"Isn\'t," they said.'

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