python dataframe astype 字段类型转换方法


            使用astype实现dataframe字段类型转换





# -*- coding: UTF-8 -*-

import pandas as pd

df = pd.DataFrame([{'col1':'a', 'col2':'1'}, {'col1':'b', 'col2':'2'}])

print df.dtypes

df['col2'] = df['col2'].astype('int')

print '-----------'

print df.dtypes

df['col2'] = df['col2'].astype('float64')

print '-----------'

print df.dtypes





输出结果：





col1  object

col2  object

dtype: object

-----------

col1  object

col2   int32

dtype: object

-----------

col1   object

col2  float64

dtype: object



注：data type list





Data type  Description

bool_  Boolean (True or False) stored as a byte

int_  Default integer type (same as C long; normally either int64 or int32)

intc  Identical to C int (normally int32 or int64)

intp  Integer used for indexing (same as C ssize_t; normally either int32 or int64)

int8  Byte (-128 to 127)

int16  Integer (-32768 to 32767)

int32  Integer (-2147483648 to 2147483647)

int64  Integer (-9223372036854775808 to 9223372036854775807)

uint8  Unsigned integer (0 to 255)

uint16 Unsigned integer (0 to 65535)

uint32 Unsigned integer (0 to 4294967295)

uint64 Unsigned integer (0 to 18446744073709551615)

float_ Shorthand for float64.

float16 Half precision float: sign bit, 5 bits exponent, 10 bits mantissa

float32 Single precision float: sign bit, 8 bits exponent, 23 bits mantissa

float64 Double precision float: sign bit, 11 bits exponent, 52 bits mantissa

complex_  Shorthand for complex128.

complex64  Complex number, represented by two 32-bit floats (real and imaginary components)

complex128 Complex number, represented by two 64-bit floats (real and imaginary components)



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