Use the split function to split the string and convert the data into a list type:
test = 'hello_world_yoyo'
print(test.split("_"))
12Result:
['hello', 'world', 'yoyo']
Use the join function to convert the data into a string:
test = ["hello", "world", "yoyo"]
print("_".join(test))Result:
hello_world_yoyo
If you do not rely on the join method provided by python, you can also use a for loop and then add the characters String splicing, but when using " " to connect strings, the result will generate a new object. When using join, the result is just to splice the elements in the original list, so join is more efficient.
The for loop is spliced as follows:
test = ["hello", "world", "yoyo"]
# 定义一个空字符串
j = ''
# 通过 for 循环打印出列表中的数据
for i in test:
j = j + "_" + i
# 因为通过上面的字符串拼接，得到的数据是“_hello_world_yoyo”，前面会多一个下划线_，所以把这个下划线去掉
print(j.lstrip("_"))Use the replace function and replace the characters:
s = 'We are happy.'
print(s.replace(' ', '%20'))
12Result:
We%20are%20happy.
for loop printing:
for i in range(1, 10):
for j in range(1, i+1):
print('{}x{}={}t'.format(j, i, i*j), end='')
print()while loop implementation:
i = 1
while i <= 9:
j = 1
while j <= i:
print("%d*%d=%-2d"%(i,j,i*j),end = ' ')# %d： 整数的占位符，'-2'代表靠左对齐，两个占位符
j += 1
print()
i += 1Result:
1x1=1 1x2=2 2x2=4 1x3=3 2x3=6 3x3=9 1x4=4 2x4=8 3x4=12 4x4=16 1x5=5 2x5=10 3x5=15 4x5=20 5x5=25 1x6=6 2x6=12 3x6=18 4x6=24 5x6=30 6x6=36 1x7=7 2x7=14 3x7=21 4x7=28 5x7=35 6x7=42 7x7=49 1x8=8 2x8=16 3x8=24 4x8=32 5x8=40 6x8=48 7x8=56 8x8=64 1x9=9 2x9=18 3x9=27 4x9=36 5x9=45 6x9=54 7x9=63 8x9=72 9x9=81
def test(): message = 'Hello, welcome to my world.' world = 'welcome' if world in message: return message.find(world) else: return -1 print(test())
Result:
7
def test(): message = 'Hello, welcome to my world.' # 计数 num = 0 # for 循环 message for i in message: # 判断如果 ‘w’ 字符串在 message 中，则 num +1 if 'w' in i: num += 1 return num print(test()) # 结果 2
def test(str_test, num, counts):
"""
:param str_test: 字符串
:param num: 字符串出现的次数
:param count: 字符串第几次出现的次数
:return:
"""
# 定义一个空数组，存放逻辑处理后的数据
list = []
# for循环字符串的数据
for i in str_test:
# 使用 count 函数，统计出所有字符串出现的次数
count = str_test.count(i, 0, len(str_test))
# 判断字符串出现的次数与设置的counts的次数相同，则将数据存放在list数组中
if count == num:
list.append(i)
# 返回第n次出现的字符串
return list[counts-1]
print(test('gbgkkdehh', 1, 2))
结果：
ddef test(): message = 'welcome to my world' world = 'world' if world in message: return True return False print(test()) 结果： True
def test(): message = 'hi how are you hello world, hello yoyo!' world = 'hello' return message.find(world) print(test()) 结果： 15
def test(string, str):
# 定义 last_position 初始值为 -1
last_position = -1
while True:
position = string.find(str, last_position+1)
if position == -1:
return last_position
last_position = position
print(test('hi how are you hello world, hello yoyo!', 'hello'))
结果：
28while True:
try:
# 判断输入是否为整数
num = int(input('输入一个整数：'))
# 不是纯数字需要重新输入
except ValueError:
print("输入的不是整数！")
continue
if num % 2 == 0:
print('偶数')
else:
print('奇数')
break
结果：
输入一个整数：100
偶数def test():
user_input = input("请输入您的姓名：")
if user_input[0] == '王':
return "用户姓王"
return "用户不姓王"
print(test())
结果：
请输入您的姓名：王总
用户姓王Use the type conversion provided by Python to convert the data input by the user into a floating point number type. If the conversion throws an exception, it is judged that the number is not composed of pure numbers.
def test(num):
try:
return float(num)
except ValueError:
return "请输入数字"
print(test('133w3'))a = 'This is string example….wow!' b = 'Welcome To My World' print(a.upper()) print(b.lower())
Python provides the strip() method to remove the leading and trailing spaces, rstrip() removes the trailing spaces, lstrip () removes leading spaces, replace(" ", "") removes all spaces.
a = 'welcome to my world ' print(a.strip())
It can also be realized through recursion:
def trim(s):
flag = 0
if s[:1]==' ':
s = s[1:]
flag = 1
if s[-1:] == ' ':
s = s[:-1]
flag = 1
if flag==1:
returntrim(s)
else:
return s
print(trim('Hello world!'))Through while loop:
def trim(s):
while(True):
flag = 0
if s[:1]==' ':
s = s[1:]
flag = 1
if s[-1:] == ' ':
s = s[:-1]
flag = 1
if flag==0:
break
return s
print(trim('Hello world!'))def test(): s = 'ajldjlajfdljfddd' # 定义一个数组存放数据 str_list = [] # for循环s字符串中的数据，然后将数据加入数组中 for i in s: # 判断如果数组中已经存在这个字符串，则将字符串移除，加入新的字符串 if i in str_list: str_list.remove(i) str_list.append(i) # 使用 sorted 方法，对字母进行排序 a = sorted(str_list) # sorted方法返回的是一个列表，这边将列表数据转换成字符串 return "".join(a) print(test()) 结果： adfjl
def test():
n = 8
for i in range(-int(n/2), int(n/2) + 1):
print(" "*abs(i), "*"*abs(n-abs(i)*2))
print(test())
结果：
**
****
******
********
******
****
**class Test:
# 计算数字的位数
def test_num(self, num):
try:
# 定义一个 length 的变量，来计算数字的长度
length = 0
while num != 0:
# 判断当 num 不为 0 的时候，则每次都除以10取整
length += 1
num = int(num) // 10
if length > 5:
return "请输入正确的数字"
return length
except ValueError:
return "请输入正确的数字"
# 逆序打印出个位数
def test_sorted(self, num):
if self.test_num(num) != "请输入正确的数字":
# 逆序打印出数字
sorted_num = num[::-1]
# 返回逆序的个位数
return sorted_num[-1]
print(Test().test_sorted('12346'))
结果：
1def test(): for num in range(100, 1000): i = num // 100 j = num // 10 % 10 k = num % 10 if i ** 3 + j ** 3 + k ** 3 == num: print(str(num) + "是水仙花数") test()
i = 1 for j in range(101): i = j + i print(i) 结果： 5051
def test(sum_to): # 定义一个初始值 sum_all = 0 # 循环想要计算的数据 for i in range(1, sum_to + 1): sum_all += i * (-1) ** (1 + i) return sum_all if __name__ == '__main__': result = test(sum_to=100) print(result) -50
def test(n): sum = 0 for i in range(1, n+1): sum += i*10+i return sum print(test(5)) 结果： 225
a = 'hello' b = 'world' c = a a = b b = c print(a, b)
For example [1, 2, 0, 2, 1], [1, 2, 3, 3, 2, 1], such arrays are all symmetric arrays. Use Python to judge whether it is a symmetric array that prints True, not False.
def test(): x = [1, 'a', 0, '2', 0, 'a', 1] # 通过下标的形式，将字符串逆序进行比对 if x == x[::-1]: return True return False print(test()) 结果： True
def test(): a = [1, 3, 5, 7, 11] # 逆序打印数组中的数据 print(a[::-1]) # 定义一个计数的变量 count = 0 for i in a: # 判断每循环列表中的一个数据，则计数器中会 +1 count += 1 # 如果计数器为奇数，则打印出来 if count % 2 != 0: print(i) test() 结果： [11, 7, 5, 3, 1] 1 5 11
a = [1, 6, 8, 11, 9, 1, 8, 6, 8, 7, 8] print(sorted(a)) 结果： [1, 1, 6, 6, 7, 8, 8, 8, 8, 9, 11]
L1 = [1, 2, 3, 11, 2, 5, 3, 2, 5, 33, 88] print(max(L1)) print(min(L1)) 结果： 88 1
The above is implemented through the functions that come with Python, as follows, you can write a calculation program yourself:
class Test(object): def __init__(self): # 测试的列表数据 self.L1 = [1, 2, 3, 11, 2, 5, 3, 2, 5, 33, 88] # 从列表中取第一个值，对于数据大小比对 self.num = self.L1[0] def test_small_num(self, count): """ :param count: count为 1，则表示计算最大值，为 2 时，表示最小值 :return: """ # for 循环查询列表中的数据 for i in self.L1: if count == 1: # 循环判断当数组中的数据比初始值小，则将初始值替换 if i > self.num: self.num = i elif count == 2: if i < self.num: self.num = i elif count != 1 or count != 2: return "请输入正确的数据" return self.num print(Test().test_small_num(1)) print(Test().test_small_num(2)) 结果： 88 1
def test(): a = ["hello", "world", "yoyo", "congratulations"] # 统计数组中第一个值的长度 length = len(a[0]) for i in a: # 循环数组中的数据，当数组中的数据比初始值length中的值长，则替换掉length的默认值 if len(i) > length: length = i return length print(test()) 结果： congratulations
def test(): L1 = [1, 2, 3, 11, 2, 5, 3, 2, 5, 33, 88] return sorted(L1)[:3] print(test()) 结果： [1, 2, 2]
30. 把列表 a = [1, -6, 2, -5, 9, 4, 20, -3] 中的数字绝对值。
def test(): a = [1, -6, 2, -5, 9, 4, 20, -3] # 定义一个数组，存放处理后的绝对值数据 lists = [] for i in a: # 使用 abs() 方法处理绝对值 lists.append(abs(i)) return lists print(test()) 结果： [1, 6, 2, 5, 9, 4, 20, 3]
The above is the detailed content of 30 Python practice questions worth collecting (with detailed explanations). For more information, please follow other related articles on the PHP Chinese website!
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