str 和 list 的共性和list的方法
阿新 • • 發佈:2018-11-25
都可以切片
test = 'abcdefghijklmn'
print (test[1:9:3])
輸出:
beh
都可以索引:
test = 'abcdefghijklmn'
print (test[-4])
輸出:
k
都是可迭代物件:
test = 'abcde'
for n in test:
print (n)
輸出:
a
b
c
d
e
都可以用in或者not in 來判斷:
test = ['a', 'b', 'c', 'd', 'e'] v = 'a' in test print(v) test = 'abcde' v = 'a' in test print(v)
輸出:
True
True
都可以修改,但是方式不同:
str修改是重新建立新的str,用replace(),join(),split(),strip()等:
test = 'bbbbbbbbbb'
p = test.replace('b','2',5) #共替換5次
print(p)
輸出:
22222bbbbb
實現刪除字元效果:
test = 'abcde'
p = test.replace('b','')
print(p)
輸出:
acde
實現比join()前後多一個字元的效果:
test = 'abcde' p = test.replace('','-') print(p)
輸出:
-a-b-c-d-e-
list修改是原來的列表上修改
用索引替換物件:
test = ['a','b','c','d','e']
test[-1] = 'k'
print(test)
輸出:
[‘a’, ‘b’, ‘c’, ‘d’, ‘k’]
用切片替換物件:
test = ['a','b','c','d','e']
test[1:3] = [1,2]
print(test)
輸出:
[‘a’, 1, 2, ‘d’, ‘e’]
del刪除索引指定的物件:
test = ['a', 'b', 'c', 'd', 'e'] del test[0] #刪除索引指定的物件 print(test) test = ['a','b','c','d','e'] del test[1:4] #刪除切片指定的物件 print(test)
輸出:
[‘b’, ‘c’, ‘d’, ‘e’]
[‘a’, ‘e’]
remove()從列表左邊開始刪除第一個指定的值:
test = ['a','b','a','d','e']
test.remove('a')
print(test)
輸出:
[‘b’, ‘a’, ‘d’, ‘e’]
pop()彈出序列末尾的值並賦值給v:
test = ['a','b','c','d','e']
v = test.pop()
print(v,test)
輸出:
e [‘a’, ‘b’, ‘c’, ‘d’]
pop()彈出索引指定的值並賦值給v:
test = ['a','b','c','d','e']
v = test.pop(0)
print(v,test)
輸出:
a [‘b’, ‘c’, ‘d’, ‘e’]
appden()在序列末尾加入某一個元素,引數為單一物件:
test1 = ['a', 'b', 12]
test1.append(['cd',34])
print(test1)
輸出:
[‘a’, ‘b’, 12, [‘cd’, 34]]
extend()在序列末尾增加一系列元素,引數為可迭代物件:
test1 = ['a', 'b', 12]
test1.extend(['cd',34])
print(test1)
輸出:
[‘a’, ‘b’, 12, ‘cd’, 34]
insert在索引指定的位置插入物件:
test = ['a','b','c','d','e']
test.insert(0,'sss')
print(test)
輸出:
[‘sss’, ‘a’, ‘b’, ‘c’, ‘d’, ‘e’]
sort()給序列永久性排序:
test = ['D','a','我','1','大','B','d','愛','3','c','4','家','b','2','A','C']
test.sort()
print(test)
輸出:
[‘1’, ‘2’, ‘3’, ‘4’, ‘A’, ‘B’, ‘C’, ‘D’, ‘a’, ‘b’, ‘c’, ‘d’, ‘大’, ‘家’, ‘我’, ‘愛’]
sort(reverse=True)給序列永久性反向排序:
test = ['D','a','我','1','大家','B','d','愛','3','c','4','b','2','A','C']
test.sort(reverse = True)
print(test)
輸出:
[‘愛’, ‘我’, ‘大家’, ‘d’, ‘c’, ‘b’, ‘a’, ‘D’, ‘C’, ‘B’, ‘A’, ‘4’, ‘3’, ‘2’, ‘1’]
sorted()將序列臨時排序:
test = ['e','b','f','a','c']
v = sorted(test)
print(v)
輸出:
[‘a’, ‘b’, ‘c’, ‘e’, ‘f’]
reverse()將序列永久性反轉順序:
test = ['家','b','2','A','C']
test.reverse()
print(test)
輸出:
[‘C’, ‘A’, ‘2’, ‘b’, ‘家’]
clear()清空列表:
test1 = ['a', 'b', 12]
test1.clear()
print(test1)
輸出:
[]
copy()淺拷貝:
test1 = ['a', 'b', 12]
v = test1.copy()
print(v)
輸出:
[‘a’, ‘b’, 12]
count()計算元素的次數:
test1 = ['a', 'b','a', 12]
v = test1.count('a')
print(v)
輸出:
2
index()從左邊開始根據值找到對應索引,沒找到會報錯:
test1 = ['a', 'b', 12,'b']
v = test1.index('b')
print(v)
輸出:
1