如何将str转换为float?"545.2222" → 545.2222如何将str转换为int?"31" → 31
相反,请参见在Python中将整数转换为字符串和将浮点转换为字符串而不舍入。
请改为使用“如何将输入读取为数字?”?关闭重复问题,其中OP从用户输入中接收到字符串并立即想要转换它,或者希望输入(在3.x中)自动转换类型。
如何将str转换为float?"545.2222" → 545.2222如何将str转换为int?"31" → 31
相反,请参见在Python中将整数转换为字符串和将浮点转换为字符串而不舍入。
请改为使用“如何将输入读取为数字?”?关闭重复问题,其中OP从用户输入中接收到字符串并立即想要转换它,或者希望输入(在3.x中)自动转换类型。
当前回答
对于数字和字符:
string_for_int = "498 results should get"
string_for_float = "498.45645765 results should get"
首次导入重新:
import re
# For getting the integer part:
print(int(re.search(r'\d+', string_for_int).group())) #498
# For getting the float part:
print(float(re.search(r'\d+\.\d+', string_for_float).group())) #498.45645765
对于简单的模型:
value1 = "10"
value2 = "10.2"
print(int(value1)) # 10
print(float(value2)) # 10.2
其他回答
def get_int_or_float(v):
number_as_float = float(v)
number_as_int = int(number_as_float)
return number_as_int if number_as_float == number_as_int else number_as_float
float(“545.2222”)和int(float(”545.2222“))
Use:
def num(s):
try:
for each in s:
yield int(each)
except ValueError:
yield float(each)
a = num(["123.55","345","44"])
print a.next()
print a.next()
这是我所能想到的最具Python风格的方式。
处理十六进制、八进制、二进制、十进制和浮点
这个解决方案将处理数字的所有字符串约定(我所知道的)。
def to_number(n):
''' Convert any number representation to a number
This covers: float, decimal, hex, and octal numbers.
'''
try:
return int(str(n), 0)
except:
try:
# Python 3 doesn't accept "010" as a valid octal. You must use the
# '0o' prefix
return int('0o' + n, 0)
except:
return float(n)
这个测试用例输出说明了我所说的内容。
======================== CAPTURED OUTPUT =========================
to_number(3735928559) = 3735928559 == 3735928559
to_number("0xFEEDFACE") = 4277009102 == 4277009102
to_number("0x0") = 0 == 0
to_number(100) = 100 == 100
to_number("42") = 42 == 42
to_number(8) = 8 == 8
to_number("0o20") = 16 == 16
to_number("020") = 16 == 16
to_number(3.14) = 3.14 == 3.14
to_number("2.72") = 2.72 == 2.72
to_number("1e3") = 1000.0 == 1000
to_number(0.001) = 0.001 == 0.001
to_number("0xA") = 10 == 10
to_number("012") = 10 == 10
to_number("0o12") = 10 == 10
to_number("0b01010") = 10 == 10
to_number("10") = 10 == 10
to_number("10.0") = 10.0 == 10
to_number("1e1") = 10.0 == 10
下面是测试:
class test_to_number(unittest.TestCase):
def test_hex(self):
# All of the following should be converted to an integer
#
values = [
# HEX
# ----------------------
# Input | Expected
# ----------------------
(0xDEADBEEF , 3735928559), # Hex
("0xFEEDFACE", 4277009102), # Hex
("0x0" , 0), # Hex
# Decimals
# ----------------------
# Input | Expected
# ----------------------
(100 , 100), # Decimal
("42" , 42), # Decimal
]
values += [
# Octals
# ----------------------
# Input | Expected
# ----------------------
(0o10 , 8), # Octal
("0o20" , 16), # Octal
("020" , 16), # Octal
]
values += [
# Floats
# ----------------------
# Input | Expected
# ----------------------
(3.14 , 3.14), # Float
("2.72" , 2.72), # Float
("1e3" , 1000), # Float
(1e-3 , 0.001), # Float
]
values += [
# All ints
# ----------------------
# Input | Expected
# ----------------------
("0xA" , 10),
("012" , 10),
("0o12" , 10),
("0b01010" , 10),
("10" , 10),
("10.0" , 10),
("1e1" , 10),
]
for _input, expected in values:
value = to_number(_input)
if isinstance(_input, str):
cmd = 'to_number("{}")'.format(_input)
else:
cmd = 'to_number({})'.format(_input)
print("{:23} = {:10} == {:10}".format(cmd, value, expected))
self.assertEqual(value, expected)
YAML解析器可以帮助您确定字符串的数据类型。使用YAML.load(),然后可以使用type(result)测试类型:
>>> import yaml
>>> a = "545.2222"
>>> result = yaml.load(a)
>>> result
545.22220000000004
>>> type(result)
<type 'float'>
>>> b = "31"
>>> result = yaml.load(b)
>>> result
31
>>> type(result)
<type 'int'>
>>> c = "HI"
>>> result = yaml.load(c)
>>> result
'HI'
>>> type(result)
<type 'str'>