If pyenv does not switch the python version, use the following command.
$ eval "$(pyenv init -)"
It has attributes (variables) and methods (functions). A class in PHP? However, initialization (storage in a variable) is not necessary to use a data type function. Data type. Available in function ()
Each data type such as split () of a character string has a function. This function is called ** method **. The method is a variable. Execute with the method name ()
a = 'tokyo,shibuya'
b = a.split(',')
print(b) # ['tokyo','shibuya']
Construction
def function name(argument)
processing
return x
Set the default value for the argument
def function name(argument=Default value)
processing
return x
#Dice data
class Dice :
def __init__(self,val=6): # ①
if val not in [4,6,8,12,20]:
raise Exception('There is no such front body') #②
self.face_num = val #③
def shoot(self):
return random.randint(1,self.face_num)
① You can specify the function to be executed when it is called (initialized) by the function of __init__.
② It is possible to display an error with raise. The numerical value of the argument is checked in the if argument in target. Error messages in parentheses for exception ('') can be displayed
③ self must be specified as an argument when creating a method in the class. Also, prefix the variables used in the methods in the class with self.
class class name(Inheritance source data type):
#When adding processing to the initialization method, also load the initialization method of the parent class
def __init__(self) :
super(name of the class,self).__init__()
#super has two arguments, a data type and self, and returns its parent class.
Additional processing
class A() :
age = 37
a = A()
a.age # 37
An object can be created by assigning the class name () to a variable. Note that if you do not add (), it will be just a copy of the class!
class A() :
age = 37
a = A
a.age = 20
a.age # 20
A.age # 20
b= A()
b.age #20
If you copy it, you will change the variable of the class when you try to change the variable of the object as described above, and when you create the object after that, that value will be the initial value.
Meaning to put yourself in the argument. Class has methods and variables
len()
str()
print()
Creates a contiguous list of integers for the number specified in int. The start position and end position can be determined by separating the arguments with. Start with the first argument. Before the second argument.
range(3) # [0,1,2]
range(1,5) # [1,2,3,4]
range(10,11) # [10]
The method that the string has. Separates the character string with the character specified in the argument and returns the result as an array.
a = 'tokyo,nagoya'
b = a.split(',')
print(b) #[tokyo, nagoya]
String.upper()
a = 'abcd'
b = a.upper()
print(b) # ABCD
Returns the first occurrence position of the character specified in the argument with 0 at the beginning
a = 'abcdefg'
b = a.index('c')
print(b) # 2
import module name
Module name.function
Others You can use as to name the module
import module name as A
A.function#=Module name.function
import random
#Random display of range-separated integer values
random.randint(1,100)
#Randomly display the values in the array
random.random.choice(Array or string)
map(function,list)
map(str,[1,2,3]) #['1','2','3']
import datetime
#Date representation
b = datetime.date(2013,12,11)
print(b) #2013-12-11
#Calculation of the day of the week (0 is Monday,6 is sunday)
c = b.weekday()
print(c) # 2
a = [1,2,3]
len(a) # 3
a = [1,2,3]
a[-1] # 3
a[-2] # 2
a = [1,2,3]
a.append(4)
print(a) # [1,2,3,4]
a = [1,2,3]
a.insert(1,5)
print(a) #[1,5,2,3]
a = [1,2,3]
a.pop(2)
print(a) #[1,2]
a = ['da','ai','oo']
a.remove('ai')
print(a) #['da','oo']
a = [1,2]
b = [3,4]
a.extend(b)
print(a) #[1,2,3,4]
a = [1,2,3]
b = sum(a)
b # 6
a = [1,2,3]
b = max(a) # 3
c = min(c) # 1
a = [1,2,3,4,5,6,7,13,15]
a[0:3] #[1,2,3]
a[2:5] #[3,4,5]
a[3:] #[4,5,6,7,13,15]
a[:3] #[1,2,3]
a = [3,2,1,4,5,6]
#Sort in ascending order
a.sort()
a # [1,2,3,4,5,6]
#Sort in reverse order
a.reverse()
a # [6,5,4,3,2,1]
Strings are also sorted in lexicographic order (uppercase> lowercase)
a = []
a = 'Inside'
b = 'Soto'
c = a + 'When' + c
c #Nakatosoto
a = '12345'
if '3' in a :
print 'true'
#Cast each element of the array as an example
a = [1,2,3]
a_str = map(str,a)
a_str # ['1','2','3']
import re
c = 'My age is 65 years old'
pat = r"(\d{1,2})age"
d = re.search(pat,c)
d.group(1) # 65
re.sub(r'pattern','Replacement character',Target data)
#Example
import re
a = 'my name is ryo, i like programing'
n = re.sub(r"\w*(ryo)\w*",'yu',a)
n # 'my name is yu, i like programing'
#Replace word position. Of the pattern()When replacing\Since it can be specified by a number, use it.
a = '1is2 3is4 5is6'
b = re.sub(r"(\d)is(\d)",r"\2is\1",a)
b # '2is1 4is3 6is5'
A function that does not have a function name is called an anonymous function. It is mainly used by putting it in a variable. It is also convenient to use it in a map that executes a function for each element of list or a filter that selects each element of list by a function.
lis = range(1,11) # [1,2,3,4,5,6,7,8,9,10]
#Take an even number from lis
lis_even = list(filter(lambda a : a % 2 == 0,lis))
print(lis_even) # [2,4,6,8,10]
#Triple each element of lis
lis_x3 = list(map(lambda a : a * 3, lis))
print(lis_x3) # [3, 6, 9, 12, 15, 18, 21, 24, 27, 30]
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