【下载文档:  python dataframe astype 字段类型转换方法.txt 】

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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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