Python list methods All In One

Python list methods All In One

Python 3

#!/usr/bin/env python3
# coding=utf-8

__author__ = 'xgqfrms'
__editor__ = 'vscode'
__version__ = '1.0.1'
__copyright__ = """
  Copyright (c) 2012-2050, xgqfrms; mailto:xgqfrms@xgqfrms.xyz
"""

"""
  /**
   *
   * @author xgqfrms
   * @license MIT
   * @copyright xgqfrms
   * @created 2022-08-17
   *
   * @description
   * @augments
   * @example
   * @link
   *
  */
"""

# python 模版 

join

arr = ['a', 'b', 'c']

strs = ''.join(arr)
print(strs)
# abc

_strs = '-'.join(arr)
print(_strs)
# a_b_c

reverse

arr = ['a', 'b', 'c']

# reverse 没有返回新 list, 没有返回值 ✅ ,  None
# arr.reverse()

print(arr.reverse())
# None

print(arr)
# cba

string find

arr = ['a', 'b', 'c']
s = 'b'

# AttributeError: 'list' object has no attribute 'find' ❌
if(arr.find(s) > -1):
  print(True)

print(arr.find('x'))

ss = 'anc'
s = 'b'

if(ss.find(s) > -1):
  print(True)

print(ss.find('x'))

list & string index

arr = ['a', 'b', 'c']
s = 'b'

print(arr.index(s))
# 1

ss = 'anc'
s = 'b'

if(ss.find(s) > -1):
  print(True)

print(ss.find('x'))
# -1

# find 比 index 更安全，index 如果找不到会报错 ❌
print(ss.index('x'))
# ValueError: substring not found ❌

pop

arr = ['a', 'b', 'c']

print(arr.pop())
# c
print(arr)
# ['a', 'b']

append

arr = ['a', 'b', 'c']
s = 'd'

print(arr.append(s))
# None

print(arr)
# ['a', 'b', 'c', 'd']

remove

arr = ['a', 'b', 'c']
s = 'b'

print(arr.remove(s))
# None
print(arr)
# ['a', 'c']

count

arr = ['a', 'b', 'c', 'b']
s = 'b'

print(arr.count(s))
# 2
print(arr.count())
# TypeError: count() takes exactly one argument (0 given) ❌

sort

strs = ['a', 'c', 'b', 'bb', 'aa', 'cc']
nums = [1, 3, 2, 21, 12, 11]

print(strs.sort())
# None
print(strs)
# ['a', 'aa', 'b', 'bb', 'c', 'cc']

print(nums.sort())
# None
print(nums)
# [1, 2, 3, 11, 12, 21]

clear

strs = ['a', 'c', 'b']
nums = [1, 3, 2]

print(strs.clear())
# None
print(strs)
# []

print(nums.clear())
# None
print(nums)
# []

copy

strs = ['a', 'c', 'b']

print(strs.copy())
# None
print(strs)

insert

strs = ['a', 'c', 'b']
s = 'd'

# print(strs.insert(s))
# TypeError: insert expected 2 arguments, got 1 ❌

# print(strs.insert(2, s))
print(strs.insert(len(strs), s))
# None

print(strs)
# ['a', 'c', 'd', 'b']

extend

strs = ['a', 'c', 'b']
s = 'd'

print(strs.extend(s))
# None
print(strs)
# ['a', 'c', 'b', 'd',]

print(strs.extend([s, s]))
# None
print(strs)
# ['a', 'c', 'b', 'd', 'd']

for...in

strs = ['a', 'c', 'b']
result = "";

for str in strs:
  result += str + "=>";

print(result)
# a=>c=>b=>

Python 函数

https://www.runoob.com/python/python-functions.html

build in function

Python 内置函数

https://www.runoob.com/python/python-built-in-functions.html

https://www.runoob.com/python/python-functions.html

min & max

data = [7, 5, 6.9, 1, 8, 42, 33, 128, 1024, 2, 8, 11, 0.4, 1024, 66, 809, 11, 8.9, 1.1, 3.42, 9, 100, 444, 78]
#your code goes here

smallest = min(data)
largest = max(data)

data.remove(smallest)
data.remove(largest)

total = 0;
for item in data:
  total += item

print(total)

# print(sum(data))

sum

data = [7, 5, 6.9, 1, 8, 42, 33, 128, 1024, 2, 8, 11, 0.4, 1024, 66, 809, 11, 8.9, 1.1, 3.42, 9, 100, 444, 78]
#your code goes here

# total = 0;
# for item in data:
#   total += item
# print(total)

print(sum(data))

range

# 左闭右开 [begin, end),  步长 step
steps = list(range(0, 10, 3))
# [0, 3, 6, 9]


arr = range(10)
print(arr)
# range(0, 10)

slice

# class slice(stop)
# class slice(start, stop[, step])

# 设置截取5个元素的切片
myslice = slice(5)    
print(myslice)
# slice(None, 5, None)

arr = range(10)
print(arr)
# range(0, 10)

# 截取 5 个元素
subArr = arr[myslice]
print(subArr)
# range(0, 5)

# list
nums = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
print(nums)
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
print(nums[myslice])
# [0, 1, 2, 3, 4]

# print(nums.slice(5))
# AttributeError: 'list' object has no attribute 'slice'

print(nums[slice(5)])
# [0, 1, 2, 3, 4]

print(slice(nums, 5, 1))
# slice([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], 5, 1)

len

nums = [1, 3, 5, 2, 4]
print(len(nums))
# 5

refs

https://www.runoob.com/python/python-func-slice.html

https://www.programiz.com/python-programming/methods/string/join

https://www.runoob.com/python3/python3-list.html

https://stackoverflow.com/questions/493819/why-is-it-string-joinlist-instead-of-list-joinstring

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