Python custom function basics

Python custom function basics#

Overview##

In order to achieve repetitive operations, simplify labor intensity (for laziness)
Source of the tutorial, python learner at station B

Calculating string functions##

# Realize the function of len function
# len is the length of the returned string
s='sunqi'
length =0for i in s:
 length +=1#Equivalent to length=length+1print(length)

5

# Function definition and call
# Encapsulate the above content in a function
# return can return multiple values
def mylen():"""Calculate string length"""
 s='sunqi'
 length =0for i in s:
  length +=1
 # return is used to return, assign external variables
 return length
# Call functions
mylen()

# The above function implements a simple call, but does not implement parameter input
# Cannot be applied to other strings
# So create a function with parameters
def mylen(s):
 length =0for i in s:
  length +=1return length
# Call functions
mylen("helloo")

# Pass multiple values
def mymax(x,y):"""Compare the size of two numbers"""
 themax=x if x>y else y
 return themax
mymax(1,4)

# Points to note
# When the calling parameter is a variable value, the function will save the result of the last run

def mytest(a,l=[]):
 # At this time l is a variable list
 l.append(a)print(l)mytest(1)
# Call again,Will add the value of the second call
mytest(2)

[1][1,2]

# Dynamic parameters
# * args
def mysum(a,b,c):
 thesum=a+b+c
 return thesum
mysum(22,33,44)
# The above parameters are fixed, if you change the number of parameters, an error will be reported
# Need dynamic parameters at this time,You can add any number of parameters
def mysum(*args):
 thesum=0for i in args:
  thesum+=i
 return thesum
mysum(22,33,44,33)

# ** kwargs

def info(**kwargs):"""Print information"""print(kwargs)
# transfer
info(name="sunqi",sex="male",age=18)

{' name':'sunqi','sex':'male','age':18}

Concluding remarks##

In today’s statistical software, there are a total of five, stata, R, python, SAS and SPSS. After reading it many times, they are all big wheels, one wheel and another. It’s difficult and annoying. Take a look at these five software. Which one is not an excellent batch? Which one is not a research pillar? They are difficult, my heart is broken, I thought for a long time, I am heartbroken, I am ashamed of myself.

love & peace