read_json() removes underscore and converts string to integer when only numbers and underscore present #17869
Description
Code Sample
import pandas as pd
df = pd.DataFrame({'test': ['34343_43434']})
json = df.to_json(orient='records')
result = pd.read_json(json, orient='records')
print(result)output:
test
0 3434343434
Problem description
Pandas appears to be converting the initial string ("34343_43434") to an integer (3434343434) and removes the underscore to do it.
This only occurs when all characters in the string (besides the underscore) are integers. For example, if the initial value were "34343_43434X" then the output would correctly "34343_43434X". This issue does not occur when dtypes=False.
Expected Output
test
0 34343_43434
Output of pd.show_versions()
[paste the output of pd.show_versions() here below this line]
INSTALLED VERSIONS
commit: None
python: 3.6.1.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 78 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None
pandas: 0.20.3
pytest: 3.0.7
pip: 9.0.1
setuptools: 27.2.0
Cython: 0.25.2
numpy: 1.12.1
scipy: 0.19.0
xarray: None
IPython: 5.3.0
sphinx: 1.5.6
patsy: 0.4.1
dateutil: 2.6.0
pytz: 2017.2
blosc: None
bottleneck: 1.2.1
tables: 3.2.2
numexpr: 2.6.2
feather: None
matplotlib: 2.0.2
openpyxl: 2.4.7
xlrd: 1.0.0
xlwt: 1.2.0
xlsxwriter: 0.9.6
lxml: 3.7.3
bs4: 4.6.0
html5lib: 0.999
sqlalchemy: 1.1.9
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
pandas_gbq: None
pandas_datareader: None