I didn't know the basics of Python

I will write down what I did not know, which is the basics of Python, in the order I knew it.

Function arguments star and doublestar

Function as an argument Add \ * (star) to make a tuple type argument Add \ ** (double star) to make dictionary type argument Example)

def print_text(*x):

def print_text(**x):

Negative OR operator (for example, when deleting duplicate lines with df)

df = df[~df.duplicated()]

Add element to list

#Either one is ok
list1 = list1 + list2

#But this is an error
list1 = list1.extend(list2)

map I use this quite often

###For example, when making a list like for###

def plus_one(i):
    return i+1

list1 = [1,2,3]
  #Since the return value of map is an iterator, enclose it in list
list2 = list(map(puls_one,list1))
    #list2 = [2,3,4]

#You can use a lambda expression
list2 = list(map(lambda x : x+1,list1))

When processing or adding to a column with a data frame for index, item in df.iterrows() It takes a lot of time to turn it with (even if you avoid the generation of Series or take some measures).

Instead, once list = list(map(func,index_list)) Make a list of the columns you want to dig in with, and later df.assign(new_low = list) Is much faster.

I think so from the experience of running with 40 million lines of df (laughs)

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